Super expression must either be null or a function, not object

15,365

Solution 1

You're doing namespace imports (* as …) that create namespace objects in your variables, which are not functions indeed like the error message says. You will want to import the default exports:

import Base from './base';

and

import Class1 from './class1';

Solution 2

When you import, you are importing the entire js file, which is an object. You need to import just the class from your js file.

To use just a class do

import {myMember} from 'my-module';

Which imports just the member called myMember.

You are doing this

import * as myModule from 'my-module';

Which imports all of the members of your file as sub-members of the myModule object.

See Importing in JS (examples from here)

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Thangakumar D
Author by

Thangakumar D

Updated on June 25, 2022

Comments

  • Thangakumar D
    Thangakumar D almost 2 years

    I get Super expression must either be null or a function, not object error when I run index.js

    I see another post here with similar error message. But looks like that is related to react!

    base.js

       export default class Base{
            constructor(title){
                console.log(title);
            }
        }
    

    Class1.js

    import * as Base from './base';
    
    export default class Class1 extends Base{
        constructor(title){
            super(title);
        }
    }
    

    index.js

    import * as Class1 from './class1';
    'use strict';
    
    function check() {
        var c = new Class1('from Index.js');
    }
    
    check();
    

    .babelrc

    { "presets": [ "es2015", "stage-1" ] }

    dependencies

    dependencies": {
        "babel-cli": "^6.24.1",
        "babel-eslint": "^7.2.3",
        "babel-plugin-add-module-exports": "^0.2.1",
        "babel-plugin-syntax-export-extensions": "^6.13.0",
        "babel-plugin-transform-runtime": "^6.23.0",
        "babel-preset-es2015": "^6.24.1",
        "babel-preset-stage-1": "^6.24.1",
        "babel-register": "^6.24.1"
      }
    

    Please help! Thanks in advance !