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!

Palaeozoic

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

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

Answer 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.

Foreshow

@Palaeozoic 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. – Foreshow

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.) – Rhinoceros

I had to add "allowSyntheticDefaultImports": true under compilerOptions in tsconfig.json file – Reaper

I came here when get runtime error moment_1.default is not a function. Then I changed import moment from 'moment'; => import * as moment from 'moment'; and this worked. – Smitty

Answer 2

This worked for me:

import moment from 'moment/src/moment'

Thuthucydides

Answer 3

A beginner JS mistake that was giving me the same error:

foobar(moment) {
  console.log(moment().whatever());
}

Naming a parameter moment breaks access to the moment() function.

Cowitch

Answer 4

AS plot in the official documentation momentJs my problems were solved via nodeJS approach:

var moment = require('moment');
moment(); //this does not emit the errors

Fraternity

Answer 5

To get moment work as a function, if you are using ES6 and babel, you must import it in this way:

import moment from 'moment'

and not, as written in the documentation

import * as moment from 'moment'

Skiest

Answer 6

Remove this

import * as moment from "moment";

add this instead

import moment from "moment";

And that is how it is used in your context

{moment(finalOrder.order.order.order.dateOrdered).format("MM-DD-YYYY")}

Unstained