How to import nock in TypeScript

[borekb]

Just a note for anyone googling this (I had a hard time...):

This syntax is used in DefinitelyTyped tests:

import nock = require('nock');

However, it doesn't work with Babel (in our case, Jest uses Babel under the covers):

SyntaxError: example.ts: `import =` is not supported by @babel/plugin-transform-typescript
    Please consider using `import <moduleName> from '<moduleName>';` alongside Typescript's --allowSyntheticDefaultImports option.

This is the recommended syntax:

import nock from 'nock';

But that yielded another error when starting the app via ts-node:

example.ts:7
const mockApi = nock('https://example.com');
                    ^
TypeError: nock_1.default is not a function

It started working when I added "esModuleInterop": true to tsconfig.json.

---

Summary:

• Use import nock from 'nock'
• Add "esModuleInterop": true to tsconfig.json

[borekb]

(Sorry if this is not the best place to post it but I intuitively searched this repo for "TypeScript" and googled as well, without much luck. Feel free to close.)

[mastermatt]

There could be discussion around whether we want to support export default too, to help with this issue. As a, primarily, TS dev these days I can appreciate this pain point.

index.js could be updated to have this

const scope = require('./lib/scope')
module.exports = scope
module.exports.default = scope

[borekb]

Would be a welcome change for sure 😄

[mastermatt]

... and to extend on @borekb summary:

"esModuleInterop": true should be the go to for any TS app especially for an new app. If, however, you have an existing codebase where turning on esModuleInterop would be a pain, the alternative is to import using: import * as nock from "nock"; to get the same results.

[borekb]

the alternative is to import using: import * as nock from "nock"; to get the same results.

That's the first thing I usually try but it doesn't work for me:

TypeError: nock is not a function

Again, this is in the context of Babel (Jest tests). It works via ts-node.

[paulmelnikow]

index.js could be updated to have this

const scope = require('./lib/scope')
module.exports = scope
module.exports.default = scope

Hmm, this seems a bit hacky solution for this problem which is an ecosystem issue.

Is it possible there is a problem with the types that is contributing to the difficulty with import nock from "nock"?

[borekb]

import nock from "nock" is importing a default export, which nock doesn't provide.

It's true that I'm fighting with this because of how Babel + TypeScript play together but it's a significant enough stack & the change for Nock would be small so I think it would be worth it.