Typescript class.default is not a constructor

Question

Creating an Angular2 app, I am facing the following problem, when calling the constructor of another class inside the constructor of first class.

First Class code

import SecondClass from './second-class'

export class FirstClass {
    someVar:string;
    secondClass:SecondClass;

    constructor(firstClass?: FirstClass) {
        someVar='test';
        secondClass= new SecondClass;
    }
}

Second Class code:

export class SecondClass {
    someOtherVar:string;

    constructor(secondClass?:SecondClass) {
        someOtherVar='test';
    }
}

Would give me the error: ORIGINAL EXCEPTION: TypeError: second_class_1.default is not a constructor

Content of ./second-class

System.register([], function(exports_1, context_1) {
    "use strict";
    var __moduleName = context_1 && context_1.id;
    var SecondClass;
    return {
        setters:[],
        execute: function() {
            SecondClass = (function () {
                function SecondClass(secondClass) {
                    this.someOtherVar='test';
                }
                return SecondClass;
            }());
            exports_1("SecondClass", SecondClass);
        }
    }
});
//# sourceMappingURL=second-class.js.map

This is the compiled output from Typescript compiler

I reverted your edit because it invalidates the answers and makes the question completely unhelpful for anyone coming along. — Aluan Haddad
– Aluan Haddad, Commented Apr 26, 2018 at 14:34

dfsq · Accepted Answer · 2016-04-24 21:59:36Z

15

Error message implies that you used named export (export class SecondClass {}) in ./second-class (not default). So it means that your import should looks something like

import {SecondClass} from './second-class'

answered Apr 24, 2016 at 21:59

dfsq

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3 Comments

Nandan Phadke Over a year ago

Thanks. Modified the code but still getting error like ORIGINAL EXCEPTION: TypeError: second_class_1.SecondClass is not a constructor

dfsq Over a year ago

Can you post contents of the './second-class'? (TypeScript, not transpiled).

Nandan Phadke Over a year ago

I have it in my question just below the FirstClass code.

Tiberiu Popescu · Accepted Answer · 2016-04-24 22:08:23Z

7

There are some errors in the code :

missing {} from import
missing () from calling the constructor
missing this from accessing Class members

First Class code

import {SecondClass} from './second-class'

export class FirstClass {
    someVar:string;
    secondClass:SecondClass;

    constructor(firstClass?: FirstClass) {
        this.someVar='test';
        this.secondClass= new SecondClass();
    }
}

Second Class code:

export class SecondClass {
    someOtherVar:string;

    constructor(secondClass?:SecondClass) {
        this.someOtherVar='test';
    }
}

answered Apr 24, 2016 at 22:08

Tiberiu Popescu

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1 Comment

Nandan Phadke Over a year ago

Thanks. These were typos when typing the question. The code, without these errors is giving said error.

Timo · Accepted Answer · 2018-04-26 14:12:31Z

0

this is too late, but I just got the same error right now. Solution is export SecondClass as default so Second Class code will be:

export default class SecondClass {
    someOtherVar:string;

    constructor(secondClass?:SecondClass) {
        this.someOtherVar='test';
    }
}

and import in other class with import SecondClass from './second-class'

answered Apr 26, 2018 at 14:12

Timo

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