How do I include a JavaScript script file in Angular and call a function from that script?

Question

I have a JavaScript file called abc.js that has a 'public' function called xyz(). I want to call that function in my Angular project. How do I do that?

Answer 1

Refer the scripts inside the angular-cli.json (angular.json when using angular 6+) file.

"scripts": [
    "../path" 
 ];

then add in typings.d.ts (create this file in src if it does not already exist)

declare var variableName:any;

Import it in your file as

import * as variable from 'variableName';

Answer 2

In order to include a global library, eg jquery.js file in the scripts array from angular-cli.json (angular.json when using angular 6+):

"scripts": [
  "../node_modules/jquery/dist/jquery.js"
]

After this, restart ng serve if it is already started.

Answer 3

Add external js file in index.html.

<script src="./assets/vendors/myjs.js"></script>

Here's myjs.js file :

var myExtObject = (function() {

    return {
      func1: function() {
        alert('function 1 called');
      },
      func2: function() {
        alert('function 2 called');
      }
    }

})(myExtObject||{})


var webGlObject = (function() { 
    return { 
      init: function() { 
        alert('webGlObject initialized');
      } 
    } 
})(webGlObject||{})

Then declare it is in component like below

demo.component.ts

declare var myExtObject: any;
declare var webGlObject: any;

constructor(){
    webGlObject.init();
}

callFunction1() {
    myExtObject.func1();
}

callFunction2() {
    myExtObject.func2();
}

demo.component.html

<div>
    <p>click below buttons for function call</p>
    <button (click)="callFunction1()">Call Function 1</button>
    <button (click)="callFunction2()">Call Function 2</button>
</div>

It's working for me...

Answer 4

You can either

import * as abc from './abc';
abc.xyz();

or

import { xyz } from './abc';
xyz()

Answer 5

I resolved this issue by adding "allowJs": true within "compilerOptions" in tsconfig.json file!

Answer 6

- Let us assume our script file custom.js looks like this: -

var utilObj = {
    dummyFunc: () => {
        console.log('Calling dummy function!');
    }
}

- Add your javascript/script file in scripts array in angular.json file.

"scripts": [
    "src/custom.js" 
 ],

Should look like this: -

- Add below code snippet in typings.d.ts. If this file doesn't exist, create one in src folder.

declare var utilObj:any;

Keep your variable name similar to property of script file. Here utilObj is the property name.

- Now, You can consume this script/js file directly in your component or .ts file.

You need not import the file in component file or .ts file now as we have given the typing defination for the script file already in typings.d.ts file.

Example: -

ngOnInit() {
  console.log('Starting Application!');
  utilObj.dummyFunc();
}

- Output: -

Answer 7

This might sound silly, but if you feel that you are properly exporting your JavaScript helper function utils/javaScriptHelperFunction.js

export function javaScriptFunction() {
   // DO HELPER FUNCTION STUFF
}

If you have done your checks as mentioned in the above answers, just close and open your code editor...start with the quick basic troubleshooting before going down the rabbit hole.

Answer 8

You can create a function in the js file which includes the function you are trying to obtain:

For example: I did a Todo-List in JS and wanted to use in my angular app.

[TODO.JS]:

Next we have to import in the component.ts where we want to use our function:

ExampleComponent.ts The links are the photos of the different parts of the code.

[example.component.ts]: