How to use global URLSearchParams in node

Question

I am writing a (client-side) JavaScript library (a node/angular module). In this library, I make use of the URLSearchParams class.

const form = new URLSearchParams(); form.set('username', data.username); form.set('password', data.pass); 

As this is a shared library, it is packed as an npm module. However, when running a mocha unit test, I get the error that URLSearchParams is not defined. The reason seems to be that node does not have URLSearchParams at the global scope, but has to be imported using require('url'):

$ node > new URLSearchParams() ReferenceError: URLSearchParams is not defined     at repl:1:5     at sigintHandlersWrap (vm.js:22:35)     at sigintHandlersWrap (vm.js:73:12)     at ContextifyScript.Script.runInThisContext (vm.js:21:12)     at REPLServer.defaultEval (repl.js:340:29)     at bound (domain.js:280:14)     at REPLServer.runBound [as eval] (domain.js:293:12)     at REPLServer.<anonymous> (repl.js:538:10)     at emitOne (events.js:101:20)     at REPLServer.emit (events.js:188:7) 

How can I make URLSearchParams available to the client-side code within node, so that I can test the library using mocha?

This is not working:

> global.URLSearchParams = require('url').URLSearchParams undefined > new URLSearchParams() TypeError: URLSearchParams is not a constructor     at repl:1:1     at sigintHandlersWrap (vm.js:22:35)     at sigintHandlersWrap (vm.js:73:12)     at ContextifyScript.Script.runInThisContext (vm.js:21:12)     at REPLServer.defaultEval (repl.js:340:29)     at bound (domain.js:280:14)     at REPLServer.runBound [as eval] (domain.js:293:12)     at REPLServer.<anonymous> (repl.js:538:10)     at emitOne (events.js:101:20)     at REPLServer.emit (events.js:188:7) 

Answer 1

Update: Node v10 has built-in availability of URLSearchParams on the global object so it can be used directly as anticipated in the question.

Older versions of Node:

One option is to set it as a global in the start-up script of the test runner:

import { URLSearchParams } from 'url'; global.URLSearchParams = URLSearchParams 

With Jest, for example, you would use the setupTestFrameworkScriptFile to point to the above start-up script.

As a side note, if you wanted to achieve a similar outcome when creating a server-side Webpack bundle of universal code you can achieve this with the Webpack ProvidePlugin:

{   name: 'server',   target: 'node',   // ...   plugins: [     // ...     new webpack.ProvidePlugin({       URLSearchParams: ['url', 'URLSearchParams'],       fetch: 'node-fetch',     }),   ], }