TypeScript import error on node

[shepherdwind]

I import this package like this:

import currency from 'currency.js';
currency(1).add(1.1);

This code work fine on webpack build, but fail on node TypeError: currency_js_1.default is not a function. I use currency.js in TypeScript project.

The npm package source exports is module.exports = currency, which should be export = currency; in d.ts file. So, I think maybe we should modify the currency.d.ts , or build result.

[scurker]

Typescript is currently tested with imports.

Would you be able to share your tsconfig.json and webpack.config.js? I'm not able to reproduce your issue.

[shepherdwind]

You example is reproduceable .

I just download you code , then run npm i && node index.js. On my compute, this step will throw error

/Downloads/1fd2ec351c01b019063b48e53803e53d-c6b1134ca6ed994fbd482d226d4f0d0f60f07559/index.js:4
currency_js_1.default(1).add(1.1);
                     ^

TypeError: currency_js_1.default is not a function
    at Object.<anonymous> (Downloads/1fd2ec351c01b019063b48e53803e53d-c6b1134ca6ed994fbd482d226d4f0d0f60f07559/index.js:4:22)
    at Module._compile (module.js:573:30)
    at Object.Module._extensions..js (module.js:584:10)
    at Module.load (module.js:507:32)
    at tryModuleLoad (module.js:470:12)
    at Function.Module._load (module.js:462:3)
    at Function.Module.runMain (module.js:609:10)
    at startup (bootstrap_node.js:158:16)

[scurker]

Thanks! I see the issue now. The typescript definition file seems to be correct, but typescript is attempting to import the commonjs module instead of the ES6 module. I want to investigate further to find the proper solution, but in the short term you should be able to use one of the following imports:

import * as currency from 'currency.js';

or

import currency = require('currency.js');

[shepherdwind]

If I use import * as like this:

import * as currency from 'currency.js';

tsc will throw error [ts] Cannot invoke an expression whose type lacks a call signature. .

I think the cjs module should change to exports.default = currency; . Or for version compatibility, module.exports = currency; module.exports.default = currency; will be more better.

But I don't know how to realize this on rollup, So I can't to send pr to fix this.

[scurker]

So here's the root of the issue. Typescript is assuming modules export a default, which can cause issues when importing cjs modules.

As such, there seems to be only 3 possible solutions:

• import * as currency from 'currency.js'
• import currency = require('currency.js')
• add allowSyntheticDefaultImports: true to your tsconfig.json

I updated the typescript definition file to allow for the first 2 statements to be used, which I should hopefully be releasing in a patch update soon.