SystemJS - moment is not a function

Question

I'm using JSPM, AngularJS, TypeScript, SystemJS and ES6 and my project is running pretty well... unless I try to use momentJS.

This is the error I get:

TypeError: moment is not a function

This is part of the code:

import * as moment from 'moment';

More:

var momentInstance = moment(value);

If I debug it, moment is an object not a function:

This is what my moment.js JSPM package looks like:

module.exports = require("npm:[email protected]/moment.js");

I've read a lot and couldn't find a way to solve this... any ideas?

Some things I've read/tried:

How to use momentjs in TypeScript with SystemJS?

https://github.com/angular-ui/ui-calendar/issues/154

https://github.com/jkuri/ng2-datepicker/issues/5

Typescript module systems on momentJS behaving strangely

https://github.com/dbushell/Pikaday/issues/153

Thanks!

Solution 1

Simply remove the grouping (* as) from your import statement:

import moment from 'moment';

Without digging too deeply in to the source code, it looks like moment usually exports a function, that has all kinds of methods and other properties attached to it.

By using * as, you're effectively grabbing all those properties and attaching them to a new object, destroying the original function. Instead, you just want the chief export (export default in ES6, module.exports object in Node.js).

Alternatively, you could do

import moment, * as moments from 'moment';

to get the moment function as moment, and all the other properties on an object called moments. This makes a little less sense when converting ES5 exports like this to ES6 style, because moment will retain the same properties.

Solution 2

This worked for me:

import moment from 'moment/src/moment'

Comments

[AlainIb]

who did you do your injection dependency of moment in angular ?

[eestein]

@AlainIb hi, thanks for your comment. I'm sorry, but do you mean why? If so, what would you recommend as an alternative? Thanks again.

[Oka]

@eestein Cheers. Here's the MDN article on import. In my opinion, it's a little too brief right now, but it does cover most of the syntax.

[uglycoyote]

I too had tried import * as moment from 'moment' which gave me the "moment is not a function" error. Changing it as you suggested to import moment from 'moment' just changes the error to moment_1.default is not a function. what is going on here? (It seems that changing the way I import has caused typescript to compile my moment() function call into a moment_1.default function call.)