如何使用mocha测试使用whatwg-fetch的代码？

Question

I'm using https://github.com/github/fetch in my app, which works fine but I would like to test my code with Mocha and babel since I'm writing ES2016.

This does not work out of the box. I'm getting:

1) testApi.js Test api error handling:
 ReferenceError: fetch is not defined
  at callApi (callApi.js:10:10)
  at Context.<anonymous> (testApi.js:8:40)

Because well, fetch is not defined. When I build for the browser fetch is exposed by webpack.

I've tried using https://github.com/bitinn/node-fetch but the api is slightly different and wants full url's instead of relative paths for example.

Is there a solution to this problem?

Answer 1

So, if anyone has this problem in the future:

• Use isomorphic-fetch
• when using webpack make sure your target is set to 'web'
• import 'isomorphic-fetch' in your index.js or otherwise root file
• import 'isomorphic-fetch' in whatever test file calls fetch (or root test file if you have one)
• your tests will now use node-fetch and your webpack will now build whatwg-fetch

Answer 2

I was able to get Mocha tests working with a ternary using node-fetch module:

// Support server-side fetch for tests.
let fetch = (typeof window === 'undefined')
  ? require('node-fetch')
  : window.fetch
;

https://github.com/bitinn/node-fetch