What is the best way to export a default object containing imported types in TypeScript?

I am currently working on creating ambient type definitions for a JavaScript utility package (similar to Lodash). I want users to be able to import modules in the following ways:

// For TypeScript or Babel

import myutils from 'myutils' // myutils = { a: [Function], b: [Function] }
import { a } from 'myutils'   // a: Function
import a from 'myutils/a'     // a: Function

// For JavaScript

const myutils = require('myutils') // myutils = { a: [Function], b: [Function] }
const { a } = require('myutils')   // a: Function
const a = require('myutils/a')     // a: Function

The package structure is as follows:

// a.js
module.exports = () => 'a'
// b.js
module.exports = () => 'b'
// index.js
module.exports = { a: require('./a'), b: require('./b') }

However, I am facing difficulties in writing proper TypeScript ambient definitions for these modules. This is what I have tried so far:

// a.d.ts
export default function a(): string
// b.d.ts
export default function b(): string
// index.d.ts
export { default as a } from './a'
export { default as b } from './b'

export default ...what?

I also attempted the following without success:

// index.d.ts
import a from './a'
import b from './b'

export { a, b }

// Member 'a' implicitly has an 'any' type, but a better type may be inferred from usage.ts(7045)
declare const _default: { a, b }

export default _default

Any insights would be greatly appreciated!

Answer №1

The issue arises from your usage of the identifiers a and b as types in the following code snippet:

declare const _default: { a, b }

This error can be resolved by using typeof a instead:

declare const _default: {
    a: typeof a,
    b: typeof b
}

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