I have this error when I compile my code in node.js, how can I fix it?
RefernceError: fetch is not defined
This is the function I am doing, it is responsible for recovering information from a specific movie database.
function getMovieTitles(substr){
pageNumber=1;
let url = 'https://jsonmock.hackerrank.com/api/movies/search/?Title=' + substr + "&page=" + pageNumber;
fetch(url).then((resp) => resp.json()).then(function(data) {
let movies = data.data;
let totPages = data.total_pages;
let sortArray = [];
for(let i=0; i<movies.length;i++){
sortArray.push(data.data[i].Title);
}
for(let i=2; i<=totPages; i++){
let newPage = i;
let url1 = 'https://jsonmock.hackerrank.com/api/movies/search/?Title=' + substr + "&page=" + newPage;
fetch(url1).then(function(response) {
var contentType = response.headers.get("content-type");
if(contentType && contentType.indexOf("application/json") !== -1) {
return response.json().then(function(json) {
//console.log(json); //uncomment this console.log to see the JSON data.
for(let i=0; i<json.data.length;i++){
sortArray.push(json.data[i].Title);
}
if(i==totPages)console.log(sortArray.sort());
});
} else {
console.log("Oops, we haven't got JSON!");
}
});
}
})
.catch(function(error) {
console.log(error);
});
}
This question is related to
javascript
node.js
Best one is Axios library for fetching.
use npm i --save axios
for installng and use it like fetch, just write axios instead of fetch and then get response in then().
You have to use the isomorphic-fetch
module to your Node
project because of Node
does not contain Fetch API
yet. for fixing this problem run below command:
npm install --save isomorphic-fetch es6-promise
After installation use below code in your project:
import "isomorphic-fetch"
Hope this answer helps you.
This is the related github issue
This bug is related to the 2.0.0 version, you can solve it by simply upgrading to version 2.1.0.
You can run
npm i [email protected]
The fetch API is not implemented in Node.
You need to use an external module for that, like node-fetch.
Install it in your Node application like this
npm i node-fetch --save
then put the line below at the top of the files where you are using the fetch API:
const fetch = require("node-fetch");
You can use cross-fetch from @lquixada
Platform agnostic: browsers, node or react native
Install
npm install --save cross-fetch
Usage
With promises:
import fetch from 'cross-fetch';
// Or just: import 'cross-fetch/polyfill';
fetch('//api.github.com/users/lquixada')
.then(res => {
if (res.status >= 400) {
throw new Error("Bad response from server");
}
return res.json();
})
.then(user => {
console.log(user);
})
.catch(err => {
console.error(err);
});
With async/await:
import fetch from 'cross-fetch';
// Or just: import 'cross-fetch/polyfill';
(async () => {
try {
const res = await fetch('//api.github.com/users/lquixada');
if (res.status >= 400) {
throw new Error("Bad response from server");
}
const user = await res.json();
console.log(user);
} catch (err) {
console.error(err);
}
})();
It seems fetch support URL scheme with "http" or "https" for CORS request.
Install node fetch library npm install node-fetch
, read the file and parse to json.
const fs = require('fs')
const readJson = filename => {
return new Promise((resolve, reject) => {
if (filename.toLowerCase().endsWith(".json")) {
fs.readFile(filename, (err, data) => {
if (err) {
reject(err)
return
}
resolve(JSON.parse(data))
})
}
else {
reject(new Error("Invalid filetype, <*.json> required."))
return
}
})
}
// usage
const filename = "../data.json"
readJson(filename).then(data => console.log(data)).catch(err => console.log(err.message))
Node.js hasn't implemented the fetch() method, but you can use one of the external modules of this fantastic execution environment for JavaScript.
In one of the answers above, "node-fetch" is cited and that's a good choice.
In your project folder (the directory where you have the .js scripts) install that module with the command:
npm i node-fetch --save
Then use it as a constant in the script you want to execute with Node.js, something like this:
const fetch = require("node-fetch");
The following works for me in Node.js 12.x:
npm i node-fetch;
to initialize the Dropbox instance:
var Dropbox = require("dropbox").Dropbox;
var dbx = new Dropbox({
accessToken: <your access token>,
fetch: require("node-fetch")
});
to e.g. upload a content (an asynchronous method used in this case):
await dbx.filesUpload({
contents: <your content>,
path: <file path>
});
Might sound silly but I simply called npm i node-fetch --save
in the wrong project. Make sure you are in the correct directory.
You should add this import in your file:
import * as fetch from 'node-fetch';
And then, run this code to add the node-fetch
:
yarn add node-fetch
If you want to avoid npm install and not running in browser, you can also use nodejs https module;
const https = require('https')
const url = "https://jsonmock.hackerrank.com/api/movies";
https.get(url, res => {
let data = '';
res.on('data', chunk => {
data += chunk;
});
res.on('end', () => {
data = JSON.parse(data);
console.log(data);
})
}).on('error', err => {
console.log(err.message);
})
If it has to be accessible with a global scope
global.fetch = require("node-fetch");
This is a quick dirty fix, please try to eliminate this usage in production code.
For those also using typescript on node-js and are getting a ReferenceError: fetch is not defined
error
npm install
these packages:
"amazon-cognito-identity-js": "3.0.11"
"node-fetch": "^2.3.0"
Then include:
import Global = NodeJS.Global;
export interface GlobalWithCognitoFix extends Global {
fetch: any
}
declare const global: GlobalWithCognitoFix;
global.fetch = require('node-fetch');
Source: Stackoverflow.com