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Some Of The Best Answers From Latest Asked Questions

How to import JSON File into a TypeScript file?

I couldn't import a different file.json too. But I resolved it like this

const swaggerDoc = require('../swagger.json')

Angular 4: no component factory found,did you add it to @NgModule.entryComponents?

In this section, you must enter the component that is used as a child in addition to declarations: [CityModalComponent](modal components) in the following section in the app.module.ts file:

 entryComponents: [
CityModalComponent
],

java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex in Android Studio 3.0

I am using Android Studio 3.0 and was facing the same problem. I add this to my gradle:

multiDexEnabled true

And it worked!

Example

android {
    compileSdkVersion 27
    buildToolsVersion '27.0.1'
    defaultConfig {
        applicationId "com.xx.xxx"
        minSdkVersion 15
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        multiDexEnabled true //Add this
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            shrinkResources true
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

And clean the project.

I get "Http failure response for (unknown url): 0 Unknown Error" instead of actual error message in Angular

If this is a node service, try the steps outlined here

Basically, it's a Cross-Origin Resource Sharing (CORS) error. More information about such errors here.

Once I updated my node service with the following lines it worked:

let express = require("express");
let app = express();

app.use(function(req, res, next) {
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");    
    next();
  });

Why AVD Manager options are not showing in Android Studio

It Seems your AVD Manager is missing from root SDK directory please follow the Steps

  1. Go to sdk\tools\lib\ and copy AVDManager.exe
  2. Paste it to root of your sdk Directory. Now you have sdk\AVD Manager.exe

Now try to run it.

Failed to resolve: com.android.support:appcompat-v7:27.+ (Dependency Error)

Find root build.gradle file and add google maven repo inside allprojects tag

repositories {
        mavenLocal()
        mavenCentral()
        maven {                                  // <-- Add this
            url 'https://maven.google.com/' 
            name 'Google'
        }
    } 

It's better to use specific version instead of variable version

compile 'com.android.support:appcompat-v7:27.0.0'

If you're using Android Plugin for Gradle 3.0.0 or latter version

repositories {
      mavenLocal()
      mavenCentral()
      google()        //---> Add this
} 

and inject dependency in this way :

implementation 'com.android.support:appcompat-v7:27.0.0'

Checkbox angular material checked by default

For check it with ngModel, make a merge between "ngModel" and "value", Example:

 <mat-checkbox [(ngModel)]="myVariable"  value="1" >Subscribe</mat-checkbox>

Where, myVariable = 1

Greeting

How can I run specific migration in laravel

use this command php artisan migrate --path=/database/migrations/my_migration.php it worked for me..

Failed to run sdkmanager --list with Java 9

Define home directories of different JDK versions in your .bashrc or .zshrc:

export JAVA_8_HOME=$(/usr/libexec/java_home -v1.8)
export JAVA_14_HOME=$(/usr/libexec/java_home -v14)

First of all use JDK version 8. Put this line the top of sdkmanager file:

export JAVA_HOME=$JAVA_8_HOME

Switch back to JDK version 14. Put this line the bottom of sdkmanager file:

export JAVA_HOME=$JAVA_14_HOME

"The specified Android SDK Build Tools version (26.0.0) is ignored..."

just clean and make project / rebuilt fixed my issue give a try :-)

How to create a stacked bar chart for my DataFrame using seaborn?

You could use pandas plot as @Bharath suggest:

import seaborn as sns
sns.set()
df.set_index('App').T.plot(kind='bar', stacked=True)

Output:

enter image description here

Updated:

from matplotlib.colors import ListedColormap df.set_index('App')\ .reindex_axis(df.set_index('App').sum().sort_values().index, axis=1)\ .T.plot(kind='bar', stacked=True, colormap=ListedColormap(sns.color_palette("GnBu", 10)), figsize=(12,6))

Updated Pandas 0.21.0+ reindex_axis is deprecated, use reindex

from matplotlib.colors import ListedColormap

df.set_index('App')\
  .reindex(df.set_index('App').sum().sort_values().index, axis=1)\
  .T.plot(kind='bar', stacked=True,
          colormap=ListedColormap(sns.color_palette("GnBu", 10)), 
          figsize=(12,6))

Output:

enter image description here

Angular : Manual redirect to route

Redirect to another page using function on component.ts file

componene.ts:

import {Router} from '@angular/router';
constructor(private router: Router) {}

OnClickFunction()
  {
    this.router.navigate(['/home']);
  }

component.html:

<div class="col-3">                  
<button (click)="OnClickFunction()" class="btn btn-secondary btn-custom mr-3">Button Name</button>
</div>

How to remove an unpushed outgoing commit in Visual Studio?

You have 2 options here to do that either to discard all your outgoing commits OR to undo specific commit ..

1- Discard all your outgoing commits:

To discard all your outgoing commits For example if you have local branch named master from remote branch, You can:

1- Rename your local branch from master to anything so you can remove it. 2- Remove the renamed branch. 3- create new branch from the master

So now you have a new branch without your commits ..

2- Undo specific commit: To undo specific commit you have to revert the unneeded by:

1- Double click on the unneeded commit. Double click on the unneeded commit 2- Click on revert Click on revert

But FYI the reverted commit will appear in the history of your commits with the revert commit ..

ImportError: libSM.so.6: cannot open shared object file: No such file or directory

I was not able to install cv2 on Anaconda-Jupyter notebook running on Ubuntu on Google Cloud Platform. But I found a way to do it as follows:

Run the following command from the ssh terminal and follow the instruction:

 sudo apt-get install libsm6 libxrender1 libfontconfig1

Once its installed Open the Jupyter notebook and run following command:

!pip install opencv-contrib-python

Note: I tried to run this command: "sudo python3 -m pip install opencv-contrib-python"but it was showing an error. But above command worked for me.

Now refresh the notebook page and check whether it's installed or not by running import cv2 in the notebook.

How to debug when Kubernetes nodes are in 'Not Ready' state

I was having similar issue because of a different reason:

Error:

cord@node1:~$ kubectl get nodes
NAME    STATUS     ROLES    AGE     VERSION
node1   Ready      master   17h     v1.13.5
node2   Ready      <none>   17h     v1.13.5
node3   NotReady   <none>   9m48s   v1.13.5

cord@node1:~$ kubectl describe node node3
Name:               node3
Conditions:
  Type             Status  LastHeartbeatTime                 LastTransitionTime                Reason                       Message
  ----             ------  -----------------                 ------------------                ------                       -------
  Ready            False   Thu, 18 Apr 2019 01:15:46 -0400   Thu, 18 Apr 2019 01:03:48 -0400   KubeletNotReady              runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized
Addresses:
  InternalIP:  192.168.2.6
  Hostname:    node3

cord@node3:~$ journalctl -u kubelet

Apr 18 01:24:50 node3 kubelet[54132]: W0418 01:24:50.649047   54132 cni.go:149] Error loading CNI config list file /etc/cni/net.d/10-calico.conflist: error parsing configuration list: no 'plugins' key
Apr 18 01:24:50 node3 kubelet[54132]: W0418 01:24:50.649086   54132 cni.go:203] Unable to update cni config: No valid networks found in /etc/cni/net.d
Apr 18 01:24:50 node3 kubelet[54132]: E0418 01:24:50.649402   54132 kubelet.go:2192] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized
Apr 18 01:24:55 node3 kubelet[54132]: W0418 01:24:55.650816   54132 cni.go:149] Error loading CNI config list file /etc/cni/net.d/10-calico.conflist: error parsing configuration list: no 'plugins' key
Apr 18 01:24:55 node3 kubelet[54132]: W0418 01:24:55.650845   54132 cni.go:203] Unable to update cni config: No valid networks found in /etc/cni/net.d
Apr 18 01:24:55 node3 kubelet[54132]: E0418 01:24:55.651056   54132 kubelet.go:2192] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized
Apr 18 01:24:57 node3 kubelet[54132]: I0418 01:24:57.248519   54132 setters.go:72] Using node IP: "192.168.2.6"

Issue:

My file: 10-calico.conflist was incorrect. Verified it from a different node and from sample file in the same directory "calico.conflist.template".

Resolution:

Changing the file, "10-calico.conflist" and restarting the service using "systemctl restart kubelet", resolved my issue:

NAME    STATUS   ROLES    AGE   VERSION
node1   Ready    master   18h   v1.13.5
node2   Ready    <none>   18h   v1.13.5
node3   Ready    <none>   48m   v1.13.5

Add items in array angular 4

Push object into your array. Try this:

export class FormComponent implements OnInit {
    name: string;
    empoloyeeID : number;
    empList: Array<{name: string, empoloyeeID: number}> = []; 
    constructor() {}
    ngOnInit() {}
    onEmpCreate(){
        console.log(this.name,this.empoloyeeID);
        this.empList.push({ name: this.name, empoloyeeID: this.empoloyeeID });
        this.name = "";
        this.empoloyeeID = 0;
    }
}

Android Studio 3.0 Execution failed for task: unable to merge dex

I had this when requested SDK version didn't match the dependencies. You can click the line highlighted and fix this clicking the red light bulb. No need to find the actual version, just let the IDE figure it out for you. And add google repo to maven config.

How to update/upgrade a package using pip?

tl;dr script to update all installed packages

If you only want to upgrade one package, refer to @borgr's answer. I often find it necessary, or at least pleasing, to upgrade all my packages at once. Currently, pip doesn't natively support that action, but with sh scripting it is simple enough. You use pip list, awk (or cut and tail), and command substitution. My normal one-liner is:

for i in $(pip list -o | awk 'NR > 2 {print $1}'); do sudo pip install -U $i; done

This will ask for the root password. If you do not have access to that, the --user option of pip or virtualenv may be something to look into.

Your CPU supports instructions that this TensorFlow binary was not compiled to use: AVX AVX2

What worked for me tho is this library https://pypi.org/project/silence-tensorflow/

Install this library and do as instructed on the page, it works like a charm!

Angular 4 checkbox change value

try this worked for me :

checkValue(event: any) {
    this.siteSelected.majeur = event;
}

How to work with progress indicator in flutter?

class Loader extends StatefulWidget {
      @override
      State createState() => LoaderState();
    }

    class LoaderState extends State<Loader> with SingleTickerProviderStateMixin {
      AnimationController controller;
      Animation<double> animation;

      @override
      void initState() {
        super.initState();
        controller = AnimationController(
            duration: Duration(milliseconds: 1200), vsync: this);
        animation = CurvedAnimation(parent: controller, curve: Curves.elasticOut);
        animation.addListener(() {
          this.setState(() {});
        });
        animation.addStatusListener((AnimationStatus status) {});
        controller.repeat();
      }

      @override
      void dispose() {
        controller.dispose();
        super.dispose();
      }

      @override
      Widget build(BuildContext context) {
        return Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Container(
              color: Colors.blue,
              height: 3.0,
              width: animation.value * 100.0,
            ),
            Padding(
              padding: EdgeInsets.only(bottom: 5.0),
            ),
            Container(
              color: Colors.blue[300],
              height: 3.0,
              width: animation.value * 75.0,
            ),
            Padding(
              padding: EdgeInsets.only(bottom: 5.0),
            ),
            Container(
              color: Colors.blue,
              height: 3.0,
              width: animation.value * 50.0,
            )
          ],
        );
      }
    }


    Expanded(
                        child: Padding(
                          padding:
                              EdgeInsets.only(left: 20.0, right: 5.0, top:20.0),
                          child: GestureDetector(
                            onTap: () {
                              Navigator.push(
                                  context,
                                  MaterialPageRoute(
                                      builder: (context) => FirstScreen()));
                            },
                            child: Container(
                                alignment: Alignment.center,
                                height: 45.0,
                                decoration: BoxDecoration(
                                    color: Color(0xFF1976D2),
                                    borderRadius: BorderRadius.circular(9.0)),
                                child: Text('Login',
                                    style: TextStyle(
                                        fontSize: 20.0, color: Colors.white))),
                          ),
                        ),
                      ),

groovy.lang.MissingPropertyException: No such property: jenkins for class: groovy.lang.Binding

Please double check that jenkins is not blocking this import. Go to script approvals and check to see if it is blocking it. If it is click allow.

https://jenkins.io/doc/book/managing/script-approval/

How to install popper.js with Bootstrap 4?

Try doing this:

npm install bootstrap jquery popper.js --save

See this page for more information: how-to-include-bootstrap-in-your-project-with-webpack

XCOPY: Overwrite all without prompt in BATCH

The solution is the /Y switch:

xcopy "C:\Users\ADMIN\Desktop\*.*" "D:\Backup\" /K /D /H /Y

find_spec_for_exe': can't find gem bundler (>= 0.a) (Gem::GemNotFoundException)

Update:

According @noraj's answer and @Niels Kristian's comment, the following command should do the job.

gem update --system
bundle install

I wrote this in case someone gets into an issue like mine.

gem install bundler shows that everythings installs well.

Fetching: bundler-1.16.0.gem (100%)
Successfully installed bundler-1.16.0
Parsing documentation for bundler-1.16.0
Installing ri documentation for bundler-1.16.0
Done installing documentation for bundler after 7 seconds
1 gem installed

When I typed bundle there was an error:

/Users/nikkov/.rvm/gems/ruby-2.4.0/bin/bundle:23:in `load': cannot load such file -- /Users/nikkov/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/bundler-1.16.0/exe/bundle (LoadError)
    from /Users/nikkov/.rvm/gems/ruby-2.4.0/bin/bundle:23:in `<main>'
    from /Users/nikkov/.rvm/gems/ruby-2.4.0/bin/ruby_executable_hooks:15:in `eval'
    from /Users/nikkov/.rvm/gems/ruby-2.4.0/bin/ruby_executable_hooks:15:in `<main>'

And in the folder /Users/nikkov/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/ there wasn't a bundler-1.16.0 folder.

I fixed this with sudo gem install bundler

INSTALL_FAILED_USER_RESTRICTED : android studio using redmi 4 device

In my case, I pressed Deny unfortunately during first time installation. So I was getting INSTALL_FAILED_USER_RESTRICTED.

You can get modify this permission for app under permissions.

Settings->Permissions->Install via USB->{Your App}

You should have enabled below options too.

Settings->Additional Settings->Privacy->Unknown Sources

Settings->Additional Settings->Developer Options->Install via USB

No provider for HttpClient

In my case, I was using a service in a sub module (NOT the root AppModule), and the HttpClientModule was imported only in the module.

So I have to modify the default scope of the service, by changing 'providedIn' to 'any' in the @Injectable decorator.

By default, if you using angular-cli to generate the service, the 'providedIn' was set to 'root'.

Hope this helps.

How to change port number in vue-cli project

In the webpack.config.js:

module.exports = {
  ......
  devServer: {
    historyApiFallback: true,
    port: 8081,   // you can change the port there
    noInfo: true,
    overlay: true
  },
  ......
}

You can change the port in the module.exports -> devServer -> port.

Then you restrat the npm run dev. You can get that.

Angular 5 Service to read local .json file

You have an alternative solution, importing directly your json.

To compile, declare this module in your typings.d.ts file

declare module "*.json" {
    const value: any;
    export default value;
}

In your code

import { data_json } from '../../path_of_your.json';

console.log(data_json)

How to reload current page in ReactJS?

use this might help

window.location.reload();

ReactJS and images in public folder

We know React is SPA. Everything is rendered from the root component by expanding to appropriate HTML from JSX.

So it does not matter where you want to use the images. Best practice is to use an absolute path (with reference to public). Do not worry about relative paths.

In your case, this should work everywhere:

"./images/logofooter.png"

How can the default node version be set using NVM?

Alert: This answer is for MacOS only

Let suppose you have 2 versions of nodeJS inside your nvm, namely v13.10.1 & v15.4.0

And, v15.4.0 is default

> nvm list
       v13.10.1
->      v15.4.0
         system
default -> 15.4.0 (-> v15.4.0)

And, you want to switch the default to v13.10.1

Follow these steps on your Mac terminal:

  1. Run the command:

    nvm alias default 13.10.1

This will make the default point to v13.10.1 as...

default -> 13.10.1 (-> v13.10.1)
  1. Open new instance of terminal. Now check the node version here as...

node -v

You will get...

v13.10.1
  1. nvm list will also show the new default version.

    nvm list

Just an info: The NodeJS versions taken as example above will have their different npm versions. You can cross-verify it in terminal by running npm -v

Save and load weights in keras

Here is a YouTube video that explains exactly what you're wanting to do: Save and load a Keras model

There are three different saving methods that Keras makes available. These are described in the video link above (with examples), as well as below.

First, the reason you're receiving the error is because you're calling load_model incorrectly.

To save and load the weights of the model, you would first use

model.save_weights('my_model_weights.h5')

to save the weights, as you've displayed. To load the weights, you would first need to build your model, and then call load_weights on the model, as in

model.load_weights('my_model_weights.h5')

Another saving technique is model.save(filepath). This save function saves:

  • The architecture of the model, allowing to re-create the model.
  • The weights of the model.
  • The training configuration (loss, optimizer).
  • The state of the optimizer, allowing to resume training exactly where you left off.

To load this saved model, you would use the following:

from keras.models import load_model
new_model = load_model(filepath)'

Lastly, model.to_json(), saves only the architecture of the model. To load the architecture, you would use

from keras.models import model_from_json
model = model_from_json(json_string)

How to import keras from tf.keras in Tensorflow?

Use the keras module from tensorflow like this:

import tensorflow as tf

Import classes

from tensorflow.python.keras.layers import Input, Dense

or use directly

dense = tf.keras.layers.Dense(...)

EDIT Tensorflow 2

from tensorflow.keras.layers import Input, Dense

and the rest stays the same.

Distribution certificate / private key not installed

  1. go to this link https://developer.apple.com/account/resources/certificates/list

  2. find certificate name in your alert upload then

  3. Revoke certificate that

  4. if you have certificate you download again
  5. upload testflight again

Angular (4, 5, 6, 7) - Simple example of slide in out animation on ngIf

The most upvoted answer is not implementing a real slide in/out (or down/up), as:

  1. It's not doing a soft transition on the height attribute. At time zero the element already has the 100% of its height producing a sudden glitch on the elements below it.
  2. When sliding out/up, the element does a translateY(-100%) and then suddenly disappears, causing another glitch on the elements below it.

You can implement a slide in and slide out like so:

my-component.ts

import { animate, style, transition, trigger } from '@angular/animations';

@Component({
  ...
  animations: [
    trigger('slideDownUp', [
      transition(':enter', [style({ height: 0 }), animate(500)]),
      transition(':leave', [animate(500, style({ height: 0 }))]),
    ]),
  ],
})

my-component.html

<div @slideDownUp *ngIf="isShowing" class="box">
  I am the content of the div!
</div>

my-component.scss

.box {
  overflow: hidden;
}

Conda activate not working?

If nothing works for you, you can specify the full path of your python environment setup by conda.

For me, I set up an environment called "testenv" using conda.

I searched all python environments using

whereis python | grep 'miniconda'

It returned a list of python environments. Then I ran my_python_file.py using the following command.

~/miniconda3/envs/testenv/bin/python3.8 my_python_file.py

You can do the same thing on windows too but looking up for python and conda python environments is a bit different.

E: Unable to locate package npm

Download the the repository key with:

curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -

Then setup the repository:

sudo sh -c "echo deb https://deb.nodesource.com/node_8.x cosmic main \
                 > /etc/apt/sources.list.d/nodesource.list"
sudo apt-get update
sudo apt-get install nodejs

How do I format {{$timestamp}} as MM/DD/YYYY in Postman?

Any future date in JavaScript (postman test uses JavaScript) can be retrieved as:

var dateNow = new Date();  
var twoWeeksFutureDate = new Date(dateNow.setDate(dateNow.getDate() + 14)).toISOString();

postman.setEnvironmentVariable("future-date", twoWeeksFutureDate);

How to add CORS request in header in Angular 5

A POST with httpClient in Angular 6 was also doing an OPTIONS request:

Headers General:

Request URL:https://hp-probook/perl-bin/muziek.pl/=/postData
Request Method:OPTIONS
Status Code:200 OK
Remote Address:127.0.0.1:443
Referrer Policy:no-referrer-when-downgrade

My Perl REST server implements the OPTIONS request with return code 200.

The next POST request Header:

Accept:*/*
Accept-Encoding:gzip, deflate, br
Accept-Language:nl-NL,nl;q=0.8,en-US;q=0.6,en;q=0.4
Access-Control-Request-Headers:content-type
Access-Control-Request-Method:POST
Connection:keep-alive
Host:hp-probook
Origin:http://localhost:4200
Referer:http://localhost:4200/
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.109 Safari/537.36

Notice Access-Control-Request-Headers:content-type.

So, my backend perl script uses the following headers:


 -"Access-Control-Allow-Origin" => '*',
 -"Access-Control-Allow-Methods" => 'GET,POST,PATCH,DELETE,PUT,OPTIONS',
 -"Access-Control-Allow-Headers" => 'Origin, Content-Type, X-Auth-Token, content-type',

With this setup the GET and POST worked for me!

How to draw checkbox or tick mark in GitHub Markdown table?

Following is how I draw a checkbox in a table!

| Checkbox Experiments | [ ] unchecked header  | [x] checked header  |
| ---------------------|:---------------------:|:-------------------:|
| checkbox             | [ ] row               | [x] row             |


Displays like this:
enter image description here

Pandas: ValueError: cannot convert float NaN to integer

ValueError: cannot convert float NaN to integer

From v0.24, you actually can. Pandas introduces Nullable Integer Data Types which allows integers to coexist with NaNs.

Given a series of whole float numbers with missing data,

s = pd.Series([1.0, 2.0, np.nan, 4.0])
s

0    1.0
1    2.0
2    NaN
3    4.0
dtype: float64

s.dtype
# dtype('float64')

You can convert it to a nullable int type (choose from one of Int16, Int32, or Int64) with,

s2 = s.astype('Int32') # note the 'I' is uppercase
s2

0      1
1      2
2    NaN
3      4
dtype: Int32

s2.dtype
# Int32Dtype()

Your column needs to have whole numbers for the cast to happen. Anything else will raise a TypeError:

s = pd.Series([1.1, 2.0, np.nan, 4.0])

s.astype('Int32')
# TypeError: cannot safely cast non-equivalent float64 to int32

Angular Material: mat-select not selecting default

A comparison between a number and a string use to be false, so, cast you selected value to a string within ngOnInit and it will work.

I had same issue, I filled the mat-select with an enum, using

Object.keys(MyAwesomeEnum).filter(k => !isNaN(Number(k)));

and I had the enum value I wanted to select...

I spent few hours struggling my mind trying to identify why it wasn't working. And I did it just after rendering all the variables being used in the mat-select, the keys collection and the selected... if you have ["0","1","2"] and you want to select 1 (which is a number) 1=="1" is false and because of that nothing is selected.

so, the solution is to cast you selected value to a string within ngOnInit and it will work.

No authenticationScheme was specified, and there was no DefaultChallengeScheme found with default authentification and custom authorization

Do not use authorization instead of authentication. I should get whole access to service all clients with header. The working code is :

public class TokenAuthenticationHandler : AuthenticationHandler<TokenAuthenticationOptions> 
{
    public IServiceProvider ServiceProvider { get; set; }

    public TokenAuthenticationHandler (IOptionsMonitor<TokenAuthenticationOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock, IServiceProvider serviceProvider) 
        : base (options, logger, encoder, clock) 
    {
        ServiceProvider = serviceProvider;
    }

    protected override Task<AuthenticateResult> HandleAuthenticateAsync () 
    {
        var headers = Request.Headers;
        var token = "X-Auth-Token".GetHeaderOrCookieValue (Request);

        if (string.IsNullOrEmpty (token)) {
            return Task.FromResult (AuthenticateResult.Fail ("Token is null"));
        }           

        bool isValidToken = false; // check token here

        if (!isValidToken) {
            return Task.FromResult (AuthenticateResult.Fail ($"Balancer not authorize token : for token={token}"));
        }

        var claims = new [] { new Claim ("token", token) };
        var identity = new ClaimsIdentity (claims, nameof (TokenAuthenticationHandler));
        var ticket = new AuthenticationTicket (new ClaimsPrincipal (identity), this.Scheme.Name);
        return Task.FromResult (AuthenticateResult.Success (ticket));
    }
}

Startup.cs :

#region Authentication
services.AddAuthentication (o => {
    o.DefaultScheme = SchemesNamesConst.TokenAuthenticationDefaultScheme;
})
.AddScheme<TokenAuthenticationOptions, TokenAuthenticationHandler> (SchemesNamesConst.TokenAuthenticationDefaultScheme, o => { });
#endregion

And mycontroller.cs

[Authorize(AuthenticationSchemes = SchemesNamesConst.TokenAuthenticationDefaultScheme)]
public class MainController : BaseController
{ ... }

I can't find TokenAuthenticationOptions now, but it was empty. I found the same class PhoneNumberAuthenticationOptions :

public class PhoneNumberAuthenticationOptions : AuthenticationSchemeOptions
{
    public Regex PhoneMask { get; set; }// = new Regex("7\\d{10}");
}

You should define static class SchemesNamesConst. Something like:

public static class SchemesNamesConst
{
    public const string TokenAuthenticationDefaultScheme = "TokenAuthenticationScheme";
}

How to reference static assets within vue javascript

Having a default structure of folders generated by Vue CLI such as src/assets you can place your image there and refer this from HTML as follows <img src="../src/assets/img/logo.png"> as well (works automatically without any changes on deployment too).

How do I POST XML data to a webservice with Postman?

Send XML requests with the raw data type, then set the Content-Type to text/xml.


  1. After creating a request, use the dropdown to change the request type to POST.

    Set request type to POST

  2. Open the Body tab and check the data type for raw.

    Setting data type to raw

  3. Open the Content-Type selection box that appears to the right and select either XML (application/xml) or XML (text/xml)

    Selecting content-type text/xml

  4. Enter your raw XML data into the input field below

    Example of XML request in Postman

  5. Click Send to submit your XML Request to the specified server.

    Clicking the Send button

Could not find tools.jar. Please check that C:\Program Files\Java\jre1.8.0_151 contains a valid JDK installation

In Eclipse

Right click Project --> Java Build Path --> Libraries

  1. Remove the JRE
  2. Click on Add Library --> JRE System Library -->Next -->Alternate JRE --> installed JRE --> Add JDK and select and Apply

Convert Json string to Json object in Swift 4

I used below code and it's working fine for me. :

let jsonText = "{\"userName\":\"Bhavsang\"}"
var dictonary:NSDictionary?
    
if let data = jsonText.dataUsingEncoding(NSUTF8StringEncoding) {
        
     do {
            dictonary =  try NSJSONSerialization.JSONObjectWithData(data, options: [.allowFragments]) as? [String:AnyObject]
        
            if let myDictionary = dictonary
              {
                  print(" User name is: \(myDictionary["userName"]!)")
              }
            } catch let error as NSError {
            
            print(error)
         }
}

What are pipe and tap methods in Angular tutorial?

You are right, the documentation lacks of those methods. However when I dug into rxjs repository, I found nice comments about tap (too long to paste here) and pipe operators:

  /**
   * Used to stitch together functional operators into a chain.
   * @method pipe
   * @return {Observable} the Observable result of all of the operators having
   * been called in the order they were passed in.
   *
   * @example
   *
   * import { map, filter, scan } from 'rxjs/operators';
   *
   * Rx.Observable.interval(1000)
   *   .pipe(
   *     filter(x => x % 2 === 0),
   *     map(x => x + x),
   *     scan((acc, x) => acc + x)
   *   )
   *   .subscribe(x => console.log(x))
   */

In brief:

Pipe: Used to stitch together functional operators into a chain. Before we could just do observable.filter().map().scan(), but since every RxJS operator is a standalone function rather than an Observable's method, we need pipe() to make a chain of those operators (see example above).

Tap: Can perform side effects with observed data but does not modify the stream in any way. Formerly called do(). You can think of it as if observable was an array over time, then tap() would be an equivalent to Array.forEach().

CSS class for pointer cursor

You can assign "button" to role attribute of any html tag/element to make pointer over it. i.e

<html-element role="button" />

How can I switch to another branch in git?

Check : git branch -a

If you are getting only one branch. Then do below steps.

  • Step 1 : git config --list
  • Step 2 : git config --unset remote.origin.fetch
  • Step 3 : git config --add remote.origin.fetch +refs/heads/*:refs/remotes/origin/*

axios post request to send form data

2020 ES6 way of doing

Having the form in html I binded in data like so:

DATA:

form: {
   name: 'Joan Cap de porc',
   email: '[email protected]',
   phone: 2323,
   query: 'cap d\ou'
   file: null,
   legal: false
},

onSubmit:

async submitForm() {
  const formData = new FormData()
  Object.keys(this.form).forEach((key) => {
    formData.append(key, this.form[key])
  })

  try {
    await this.$axios.post('/ajax/contact/contact-us', formData)
    this.$emit('formSent')
  } catch (err) {
    this.errors.push('form_error')
  }
}

forEach() in React JSX does not output any HTML

You need to pass an array of element to jsx. The problem is that forEach does not return anything (i.e it returns undefined). So it's better to use map because map returns an array:

class QuestionSet extends Component {
render(){ 
    <div className="container">
       <h1>{this.props.question.text}</h1>
       {this.props.question.answers.map((answer, i) => {     
           console.log("Entered");                 
           // Return the element. Also pass key     
           return (<Answer key={answer} answer={answer} />) 
        })}
}

export default QuestionSet;

Is ConfigurationManager.AppSettings available in .NET Core 2.0?

I know it's a bit too late, but maybe someone is looking for easy way to access appsettings in .net core app. in API constructor add the following:

public class TargetClassController : ControllerBase
{
    private readonly IConfiguration _config;

    public TargetClassController(IConfiguration config)
    {
        _config = config;
    }

    [HttpGet("{id:int}")]
    public async Task<ActionResult<DTOResponse>> Get(int id)
    {
        var config = _config["YourKeySection:key"];
    }
}

Exception : AAPT2 error: check logs for details

style="?android:attr/android:progressBarStyleSmall"

to

style="?android:attr/progressBarStyleSmall"

what does numpy ndarray shape do?

array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]])

enter image description here

Unable to import path from django.urls

For those who are using python 2.7, python2.7 don't support django 2 so you can't install django.urls. If you are already using python 3.6 so you need to upgrade django to latest version which is greater than 2.

  • On PowerShell

    pip install -U django

  • Verification

>

PS C:\Users\xyz> python
Python 3.6.6 |Anaconda, Inc.| (default, Jul 25 2018, 15:27:00) [MSC v.1910 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.

>>> from django.urls import path
>>>

As next prompt came, it means it is installed now and ready to use.

Property 'value' does not exist on type 'Readonly<{}>'

If you don't want to pass interface state or props model you can try this

class App extends React.Component <any, any>

The type WebMvcConfigurerAdapter is deprecated

Use org.springframework.web.servlet.config.annotation.WebMvcConfigurer

With Spring Boot 2.1.4.RELEASE (Spring Framework 5.1.6.RELEASE), do like this

package vn.bkit;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter; // Deprecated.
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@EnableWebMvc
public class MvcConfiguration implements WebMvcConfigurer {

    @Bean
    public ViewResolver getViewResolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/");
        resolver.setSuffix(".html");
        return resolver;
    }

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

}

When I run `npm install`, it returns with `ERR! code EINTEGRITY` (npm 5.3.0)

SherylHohman's answer solved the issue I had, but only after I switched my internet connection. Intitially, I was on the hard-line connection at work, and I switched to the WiFi connection at work, but that still didn't work.

As a last resort, I switched my WiFi to a pocket-WiFi, and running the following worked well:

npm cache verify

npm install -g create-react-app

create-react-app app-name

Hope this helps others.

regex match any single character (one character only)

Simple answer

If you want to match single character, put it inside those brackets [ ]

Examples

  • match + ...... [+] or +
  • match a ...... a
  • match & ...... &

...and so on. You can check your regular expresion online on this site: https://regex101.com/

(updated based on comment)

How to extract table as text from the PDF using Python?

If your pdf is text-based and not a scanned document (i.e. if you can click and drag to select text in your table in a PDF viewer), then you can use the module camelot-py with

import camelot
tables = camelot.read_pdf('foo.pdf')

You then can choose how you want to save the tables (as csv, json, excel, html, sqlite), and whether the output should be compressed in a ZIP archive.

tables.export('foo.csv', f='csv', compress=False)

Edit: tabula-py appears roughly 6 times faster than camelot-py so that should be used instead.

import camelot
import cProfile
import pstats
import tabula

cmd_tabula = "tabula.read_pdf('table.pdf', pages='1', lattice=True)"
prof_tabula = cProfile.Profile().run(cmd_tabula)
time_tabula = pstats.Stats(prof_tabula).total_tt

cmd_camelot = "camelot.read_pdf('table.pdf', pages='1', flavor='lattice')"
prof_camelot = cProfile.Profile().run(cmd_camelot)
time_camelot = pstats.Stats(prof_camelot).total_tt

print(time_tabula, time_camelot, time_camelot/time_tabula)

gave

1.8495559890000015 11.057014036000016 5.978199147125147

startForeground fail after upgrade to Android 8.1

After some tinkering for a while with different solutions i found out that one must create a notification channel in Android 8.1 and above.

private fun startForeground() {
    val channelId =
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                createNotificationChannel("my_service", "My Background Service")
            } else {
                // If earlier version channel ID is not used
                // https://developer.android.com/reference/android/support/v4/app/NotificationCompat.Builder.html#NotificationCompat.Builder(android.content.Context)
                ""
            }

    val notificationBuilder = NotificationCompat.Builder(this, channelId )
    val notification = notificationBuilder.setOngoing(true)
            .setSmallIcon(R.mipmap.ic_launcher)
            .setPriority(PRIORITY_MIN)
            .setCategory(Notification.CATEGORY_SERVICE)
            .build()
    startForeground(101, notification)
}

@RequiresApi(Build.VERSION_CODES.O)
private fun createNotificationChannel(channelId: String, channelName: String): String{
    val chan = NotificationChannel(channelId,
            channelName, NotificationManager.IMPORTANCE_NONE)
    chan.lightColor = Color.BLUE
    chan.lockscreenVisibility = Notification.VISIBILITY_PRIVATE
    val service = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
    service.createNotificationChannel(chan)
    return channelId
}

From my understanding background services are now displayed as normal notifications that the user then can select to not show by deselecting the notification channel.

Update: Also don't forget to add the foreground permission as required Android P:

<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />

Angular 4 - get input value

You can also use template reference variables

<form (submit)="onSubmit(player.value)">
   <input #player placeholder="player name">
</form>
onSubmit(playerName: string) {
  console.log(playerName)
}

Jquery AJAX: No 'Access-Control-Allow-Origin' header is present on the requested resource

If the requested resource of the server is using Flask. Install Flask-CORS.

Failed to load resource: the server responded with a status of 404 (Not Found) css

you have defined the public dir in app root/public

app.use(express.static(__dirname + '/public')); 

so you have to use:

./css/main.css

No provider for Http StaticInjectorError

In order to use Http in your app you will need to add the HttpModule to your app.module.ts:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule, ErrorHandler } from '@angular/core';
import { HttpModule } from '@angular/http';
...
  imports: [
    BrowserModule,
    HttpModule,
    IonicModule.forRoot(MyApp),
    IonicStorageModule.forRoot()
  ]

EDIT

As mentioned in the comment below, HttpModule is deprecated now, use import { HttpClientModule } from '@angular/common/http'; Make sure HttpClientModule in your imports:[] array

VS 2017 Git Local Commit DB.lock error on every commit

Just add the .vs folder to the .gitignore file.

Here is the template for Visual Studio from GitHub's collection of .gitignore templates, as an example:
https://github.com/github/gitignore/blob/master/VisualStudio.gitignore


If you have any trouble adding the .gitignore file, just follow these steps:

  1. On the Team Explorer's window, go to Settings.

Team Explorer - Settings

  1. Then access Repository Settings.

Repository Settings

  1. Finally, click Add in the Ignore File section.

enter image description here

Done. ;)
This default file already includes the .vs folder.

enter image description here

Class has been compiled by a more recent version of the Java Environment

You can try this way

javac --release 8 yourClass.java

How to get query parameters from URL in Angular 5?

Angular Router provides method parseUrl(url: string) that parses url into UrlTree. One of the properties of UrlTree are queryParams. So you can do sth like:

this.router.parseUrl(this.router.url).queryParams[key] || '';

Could not resolve com.android.support:appcompat-v7:26.1.0 in Android Studio new project

this work for me. add configurations.all in app/build.gradle

android {
    configurations.all {
        resolutionStrategy.force 'com.android.support:support-annotations:27.1.1'
    }
}

How to add a border to a widget in Flutter?

As stated in the documentation, flutter prefer composition over parameters. Most of the time what you're looking for is not a property, but instead a wrapper (and sometimes a few helpers/"builder")

For borders what you want is DecoratedBox, which has a decoration property that defines borders ; but also background images or shadows.

Alternatively like @Aziza said, you can use Container. Which is the combination of DecoratedBox, SizedBox and a few other useful widgets.

Where to declare variable in react js

Assuming that onMove is an event handler, it is likely that its context is something other than the instance of MyContainer, i.e. this points to something different.

You can manually bind the context of the function during the construction of the instance via Function.bind:

class MyContainer extends Component {
  constructor(props) {
    super(props);

    this.onMove = this.onMove.bind(this);

    this.test = "this is a test";
  }

  onMove() {
    console.log(this.test);
  }
}

Also, test !== testVariable.

Change the default base url for axios

Instead of

this.$axios.get('items')

use

this.$axios({ url: 'items', baseURL: 'http://new-url.com' })

If you don't pass method: 'XXX' then by default, it will send via get method.

Request Config: https://github.com/axios/axios#request-config

NullInjectorError: No provider for AngularFirestore

For AngularFire2 Latest version

Install AngularFire2

$ npm install --save firebase @angular/fire

Then update app.module.ts file

    import { BrowserModule } from '@angular/platform-browser';
    import { NgModule } from '@angular/core';

    import { AppComponent } from './app.component';
    import { FormsModule } from '@angular/forms';


    import { AngularFireModule } from '@angular/fire';
    import { AngularFireDatabaseModule } from '@angular/fire/database';
    import { environment } from '../environments/environment';
    import { AngularFirestoreModule } from '@angular/fire/firestore';


    @NgModule({
      declarations: [
        AppComponent
      ],
      imports: [
        BrowserModule,
        FormsModule,

        AngularFireModule.initializeApp(environment.firebase),
        AngularFirestoreModule,
        AngularFireDatabaseModule
      ],
      providers: [],
      bootstrap: [AppComponent]
    })
    export class AppModule { }

Check FireStore CRUD operation tutorial here

enter image description here

How to access Anaconda command prompt in Windows 10 (64-bit)

Go with the mouse to the Windows Icon (lower left) and start typing "Anaconda". There should show up some matching entries. Select "Anaconda Prompt". A new command window, named "Anaconda Prompt" will open. Now, you can work from there with Python, conda and other tools.

How to shift a block of code left/right by one space in VSCode?

Have a look at File > Preferences > Keyboard Shortcuts (or Ctrl+K Ctrl+S)

Search for cursorColumnSelectDown or cursorColumnSelectUp which will give you the relevent keyboard shortcut. For me it is Shift+Alt+Down/Up Arrow

What is the use of verbose in Keras while validating the model?

verbose: Integer. 0, 1, or 2. Verbosity mode.

Verbose=0 (silent)

Verbose=1 (progress bar)

Train on 186219 samples, validate on 20691 samples
Epoch 1/2
186219/186219 [==============================] - 85s 455us/step - loss: 0.5815 - acc: 
0.7728 - val_loss: 0.4917 - val_acc: 0.8029
Train on 186219 samples, validate on 20691 samples
Epoch 2/2
186219/186219 [==============================] - 84s 451us/step - loss: 0.4921 - acc: 
0.8071 - val_loss: 0.4617 - val_acc: 0.8168

Verbose=2 (one line per epoch)

Train on 186219 samples, validate on 20691 samples
Epoch 1/1
 - 88s - loss: 0.5746 - acc: 0.7753 - val_loss: 0.4816 - val_acc: 0.8075
Train on 186219 samples, validate on 20691 samples
Epoch 1/1
 - 88s - loss: 0.4880 - acc: 0.8076 - val_loss: 0.5199 - val_acc: 0.8046

GitLab remote: HTTP Basic: Access denied and fatal Authentication

   git config --system --unset credential.helper

then enter new password for Git remote server.

JS map return object

Use .map without return in simple way. Also start using let and const instead of var because let and const is more recommended

_x000D_
_x000D_
const rockets = [_x000D_
    { country:'Russia', launches:32 },_x000D_
    { country:'US', launches:23 },_x000D_
    { country:'China', launches:16 },_x000D_
    { country:'Europe(ESA)', launches:7 },_x000D_
    { country:'India', launches:4 },_x000D_
    { country:'Japan', launches:3 }_x000D_
];_x000D_
_x000D_
const launchOptimistic = rockets.map(elem => (_x000D_
  {_x000D_
    country: elem.country,_x000D_
    launches: elem.launches+10_x000D_
  } _x000D_
));_x000D_
_x000D_
console.log(launchOptimistic);
_x000D_
_x000D_
_x000D_

How to start up spring-boot application via command line?

1.Run Spring Boot app with java -jar command

To run your Spring Boot app from a command line in a Terminal window you can use java -jar command. This is provided your Spring Boot app was packaged as an executable jar file.

java -jar target/app-0.0.1-SNAPSHOT.jar

2.Run Spring Boot app using Maven

You can also use Maven plugin to run your Spring Boot app. Use the below command to run your Spring Boot app with Maven plugin:

mvn spring-boot:run

3.Run Spring Boot App with Gradle

And if you use Gradle you can run the Spring Boot app with the following command:

gradle bootRun

How to Refresh a Component in Angular

This can be achieved via a hack, Navigate to some sample component and then navigate to the component that you want to reload.

this.router.navigateByUrl('/SampleComponent', { skipLocationChange: true });
this.router.navigate(["yourLandingComponent"]);

"Could not get any response" response when using postman with subdomain

After all the above methods like turning OFF SSL certificate verification, turning ON only Use System Proxy and removing HTTP_PROXY and HTTPS_PROXY system environment variables, it worked.

Note: Had to restart the Postman app, since the environment variables were changed.

Font Awesome 5 font-family issue

I found a solution.

  • Integrate fontawesome-all.css
  • At the end of file Search the second @font-face and replace

    font-family: 'Font Awesome 5 Free';

With

font-family: 'Font Awesome 5 FreeR';

And replace:

.far {
  font-family: 'Font Awesome 5 Free';
  font-weight: 400; }

With

.far {
  font-family: 'Font Awesome 5 FreeR';
  font-weight: 400; }

React Native version mismatch

Opene projectdir/android/app/build.gradle

Try:

compile("com.facebook.react:react-native:0.51.0") { force = true }

Instead of compile "com.facebook.react:react-native:0.51.0" { force = true }

Ref.: Link

Android Studio AVD - Emulator: Process finished with exit code 1

Check android studio event log as it could be low storage issue.

emulator: ERROR: Not enough disk space to run AVD 'Nexus_5_API_21'. Exiting...

Android Studio Emulator and "Process finished with exit code 0"

I restarted Android Studio and create a new device in AVD MANAGER then I have increased the RAM size of emulator and it works nicely.

UPDATED Sometimes it happens when you close emulator during building the App in to emulator.

installing urllib in Python3.6

This happens because your local module named urllib.py shadows the installed requests module you are trying to use. The current directory is preapended to sys.path, so the local name takes precedence over the installed name.

An extra debugging tip when this comes up is to look at the Traceback carefully, and realize that the name of your script in question is matching the module you are trying to import.

Rename your file to something else like url.py. Then It is working fine. Hope it helps!

How to show code but hide output in RMarkdown?

To hide warnings, you can also do {r, warning=FALSE}

NPM Install Error:Unexpected end of JSON input while parsing near '...nt-webpack-plugin":"0'

It's simple

npm cache clean --force

then install node dependensis by

npm install

db.collection is not a function when using MongoClient v3.0

I solved it easily via running these codes:

 npm uninstall mongodb --save

 npm install [email protected] --save

Happy Coding!

pip install returning invalid syntax

You need to run pip install in the command prompt, outside from a python interpreter ! Try to exit python and re try :)

Docker: "no matching manifest for windows/amd64 in the manifest list entries"

Another possible way to do this:

In system tray, right click on docker icon, then click on Switch to Linux containers.

(Docker for Windows, Community Edition, version 18.03.1)

Python: Pandas pd.read_excel giving ImportError: Install xlrd >= 0.9.0 for Excel support

Was getting the error while I was using jupyter.

ModuleNotFoundError: No module named 'xlrd'
...
ImportError: Install xlrd >= 0.9.0 for Excel support

it was resolved for me after using.

!pip install xlrd

How to connect TFS in Visual Studio code

It seems that the extension cannot be found anymore using "Visual Studio Team Services". Instead, by following the link in Using Visual Studio Code & Team Foundation Version Control on "Get the TFVC plugin working in Visual Studio Code" you get to the Azure Repos Extension for Visual Studio Code GitHub. There it is explained that you now have to look for "Team Azure Repos".

Also, please note, that with the new Settings editor in Visual Studio Code the additional slashes do not have to be added. The path to tf.exe for VS 2017 - if specified using the "user friendly" Settings editor - would be just

C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\CommonExtensions\Microsoft\TeamFoundation\Team Explorer\TF.exe

Angular 5 Scroll to top on every Route click

Angular 6.1 and later:

You can use built in solution available in Angular 6.1+ with option scrollPositionRestoration: 'enabled' to achieve the same.

@NgModule({
  imports: [RouterModule.forRoot(routes,{
    scrollPositionRestoration: 'enabled'
  })],
  exports: [RouterModule]
})

Angular 6.0 and earlier:

import { Component, OnInit } from '@angular/core';
import { Router, NavigationStart, NavigationEnd } from '@angular/router';
import { Location, PopStateEvent } from "@angular/common";

@Component({
    selector: 'my-app',
    template: '<ng-content></ng-content>',
})
export class MyAppComponent implements OnInit {

    private lastPoppedUrl: string;
    private yScrollStack: number[] = [];

    constructor(private router: Router, private location: Location) { }

    ngOnInit() {
        this.location.subscribe((ev:PopStateEvent) => {
            this.lastPoppedUrl = ev.url;
        });
        this.router.events.subscribe((ev:any) => {
            if (ev instanceof NavigationStart) {
                if (ev.url != this.lastPoppedUrl)
                    this.yScrollStack.push(window.scrollY);
            } else if (ev instanceof NavigationEnd) {
                if (ev.url == this.lastPoppedUrl) {
                    this.lastPoppedUrl = undefined;
                    window.scrollTo(0, this.yScrollStack.pop());
                } else
                    window.scrollTo(0, 0);
            }
        });
    }
}

Note: The expected behavior is that when you navigate back to the page, it should remain scrolled down to the same location it was when you clicked on the link, but scrolling to the top when arriving at every page.

Test process.env with Jest

Jest's setupFiles is the proper way to handle this, and you need not install dotenv, nor use an .env file at all, to make it work.

jest.config.js:

module.exports = {
  setupFiles: ["<rootDir>/.jest/setEnvVars.js"]
};

.jest/setEnvVars.js:

process.env.MY_CUSTOM_TEST_ENV_VAR = 'foo'

That's it.