[javascript] remove item from stored array in angular 2

I want to remove an item from a stored array in angular 2, with Type Script. I am using a service called Data Service, the DataService Code:

export class DataService {

    private data: string[] = [];

    addData(msg: string) {
        this.data.push(msg);
    }

    getData() {
        return this.data;
    }

    deleteMsg(msg: string) {
        delete [this.data.indexOf(msg)];
    }
}

And my component class:

import {Component} from '@angular/core'
import {LogService} from './log.service'
import {DataService} from './data.service'

@Component({
    selector: 'tests',
    template:
            `
        <div class="container">
            <h2>Testing Component</h2>
            <div class="row">
                <input type="text" placeholder="log meassage" #logo>
                <button class="btn btn-md btn-primary" (click)="logM(logo.value)">log</button>
                <button class="btn btn-md btn-success" (click)="store(logo.value)">store</button>
                <button class="btn btn-md btn-danger" (click)="send()">send</button>
                <button class="btn btn-md " (click)="show()">Show Storage</button>
                <button (click)="logarray()">log array</button>
            </div>
            <div class="col-xs-12">
                <ul class="list-group">
                    <li *ngFor="let item of items" class="list-group-item" #ival>
                        {{item}}
                        <button class="pull-right btn btn-sm btn-warning" (click)="deleteItem(ival.value)">Delete
                        </button>
                    </li>
                </ul>
            </div>
            <h3>{{value}}</h3>
            <br>
        </div>
    `
})

export class TestsComponent {

    items: string[] = [];

    constructor(
        private logService: LogService,
        private dataService: DataService) {

    }

    logM(message: string) {
        this.logService.WriteToLog(message);
    }

    store(message: string) {
        this.dataService.addData(message);
    }

    send(message: string) {
    }

    show() {
        this.items = this.dataService.getData();
    }

    deleteItem(message: string) {
        this.dataService.deleteMsg(message);
    }

    logarray() {
        this.logService.WriteToLog(this.items.toString());
    }
}

Now, everything is working good except when I try to delete an item. The log shows me that the item is still in the array, and therefore is still shown on the page. How can I remove the item after selecting it with the delete button??

This question is related to javascript angular typescript

The answer is


Sometimes, splice is not enough especially if your array is involved in a FILTER logic. So, first of all you could check if your element does exist to be absolute sure to remove that exact element:

if (array.find(x => x == element)) {
   array.splice(array.findIndex(x => x == element), 1);
}

I think the Angular 2 way of doing this is the filter method:

this.data = this.data.filter(item => item !== data_item);

where data_item is the item that should be deleted


Don't use delete to remove an item from array and use splice() instead.

this.data.splice(this.data.indexOf(msg), 1);

See a similar question: How do I remove a particular element from an array in JavaScript?

Note, that TypeScript is a superset of ES6 (arrays are the same in both TypeScript and JavaScript) so feel free to look for JavaScript solutions even when working with TypeScript.


//declaration 
list: Array<any> = new Array<any>(); 

//remove item from an array 
removeitem() 
{
const index = this.list.findIndex(user => user._id === 2); 
this.list.splice(index, 1); 
}

<tbody *ngFor="let emp of $emps;let i=index">

<button (click)="deleteEmployee(i)">Delete</button></td>

and

deleteEmployee(i)
{
  this.$emps.splice(i,1);
}

This can be achieved as follows:

this.itemArr = this.itemArr.filter( h => h.id !== ID);


You can use like this:

removeDepartment(name: string): void {
    this.departments = this.departments.filter(item => item != name);
  }

You can delete the data from array

this.data.splice(index, 1);

That work for me

 this.array.pop(index);

 for example index = 3 

 this.array.pop(3);

Use splice() to remove item from the array its refresh the array index to be consequence.

delete will remove the item from the array but its not refresh the array index which means if you want to remove third item from four array items the index of elements will be after delete the element 0,1,4

this.data.splice(this.data.indexOf(msg), 1)

Examples related to javascript

need to add a class to an element How to make a variable accessible outside a function? Hide Signs that Meteor.js was Used How to create a showdown.js markdown extension Please help me convert this script to a simple image slider Highlight Anchor Links when user manually scrolls? Summing radio input values How to execute an action before close metro app WinJS javascript, for loop defines a dynamic variable name Getting all files in directory with ajax

Examples related to angular

error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class error TS1086: An accessor cannot be declared in an ambient context in Angular 9 TS1086: An accessor cannot be declared in ambient context @angular/material/index.d.ts' is not a module Why powershell does not run Angular commands? error: This is probably not a problem with npm. There is likely additional logging output above Angular @ViewChild() error: Expected 2 arguments, but got 1 Schema validation failed with the following errors: Data path ".builders['app-shell']" should have required property 'class' Access blocked by CORS policy: Response to preflight request doesn't pass access control check origin 'http://localhost:4200' has been blocked by CORS policy in Angular7

Examples related to typescript

TS1086: An accessor cannot be declared in ambient context Element implicitly has an 'any' type because expression of type 'string' can't be used to index Angular @ViewChild() error: Expected 2 arguments, but got 1 Typescript: No index signature with a parameter of type 'string' was found on type '{ "A": string; } Understanding esModuleInterop in tsconfig file How can I solve the error 'TS2532: Object is possibly 'undefined'? Typescript: Type 'string | undefined' is not assignable to type 'string' Typescript: Type X is missing the following properties from type Y length, pop, push, concat, and 26 more. [2740] Can't perform a React state update on an unmounted component TypeScript and React - children type?