Supports running mocks in Node

[kettanaito]

Changes

• Adds support for running the same mock definition in Node environment.
• Breaking: req.url is now an instance of URL, not a string.
• Breaking: req.query is removed in favor of req.url.searchParams.

GitHub

• Closes Question: How to reuse the same mocked APIs to run Jest tests? #104
• Closes Use URL instance in "req.url" #158
• Fixes Worker cannot serialize request headers with multiple values #154

Roadmap

• Configure build to produce node-oriented module with setupServer
• Ensure the node-oriented part is TypeScript-ready
• Convert intercepted request to mocked request (headers, params, query, etc.)
• Deal with res() function, that uses new Headers() instance, which does not exist in Node (also affecting ctx.fetch(): ctx.fetch() not keeping original headers #145, Issue #145 ctx.fetch() not keeping original headers #149)
• Provide a basic set of integration tests (fetch/http/https/xhr)
• Configure node bundle to properly rely on system modules (https, tty, etc.).
• Resolve the circular EventEmitter dependency issue:

(!) Circular dependencies
node_modules/util/util.js -> node_modules/util/node_modules/inherits/inherits.js -> node_modules/util/util.js
node_modules/util/util.js -> node_modules/util/node_modules/inherits/inherits.js -> /Users/kettanaito/Projects/mswjs/msw/node_modules/util/util.js?commonjs-proxy -> node_modules/util/util.js
[!] Error: 'EventEmitter' is not exported by node_modules/events/events.js, imported by node_modules/node-request-interceptor/lib/http/ClientRequest/Socket.js
https://rollupjs.org/guide/en/#error-name-is-not-exported-by-module
node_modules/node-request-interceptor/lib/http/ClientRequest/Socket.js (1:9)
1: import { EventEmitter } from 'events';
            ^
2: export class Socket extends EventEmitter {
3:     constructor(options, socketOptions) {
Error: 'EventEmitter' is not exported by node_modules/events/events.js, imported by node_modules/node-request-interceptor/lib/http/ClientRequest/Socket.js

• Remove Node-related modules from rest-deps.js chunk.

Testing scenarios

CRA + @testing-library/react

• Relative request URLs fail during interception (Requests to relative URL fail interceptors#7, resolved in XHR: Supports relative request URL interceptors#8):

    TypeError: Invalid URL: /login

      2152 |             this.readyState = this.LOADING;
      2153 |             this.data = data || '';
    > 2154 |             const url = new URL(this.url);
           |                         ^
      2155 |             const req = {
      2156 |                 url: cleanUrl(url),
      2157 |                 method: this.method,

[kettanaito]

After adopting the headers-utils library the headers of the mocked response are joined with a ",", not ", " (missing space). That is a minor difference, and shouldn't affect anything, but I'd like to debug why exactly that happened.

[kettanaito]

Need to make sure this is the expected behavior from Rollup:

(!) Unresolved dependencies
https://rollupjs.org/guide/en/#warning-treating-module-as-external-dependency
http (imported by node_modules/node-request-interceptor/lib/http/override.js, http?commonjs-external, node_modules/node-request-interceptor/lib/http/ClientRequest/ClientRequestOverride.js)
https (imported by node_modules/node-request-interceptor/lib/http/override.js, https?commonjs-external)
util (imported by node_modules/node-request-interceptor/lib/http/ClientRequest/ClientRequestOverride.js, node_modules/debug/src/node.js, util?commonjs-external)
tty (imported by node_modules/debug/src/node.js, tty?commonjs-external, node_modules/supports-color/index.js)
events (imported by node_modules/node-request-interceptor/lib/http/ClientRequest/Socket.js)
os (imported by node_modules/supports-color/index.js, os?commonjs-external)
(!) `this` has been rewritten to `undefined`
https://rollupjs.org/guide/en/#error-this-is-undefined
node_modules/node-request-interceptor/lib/index.js
3: import require$$0 from 'debug?commonjs-proxy';
4:
5: var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
                    ^
6:     function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
7:     return new (P || (P = Promise))(function (resolve, reject) {
...and 1 other occurrence
node_modules/node-request-interceptor/lib/http/ClientRequest/ClientRequestOverride.js
3: import require$$0 from 'debug?commonjs-proxy';
4:
5: var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
                    ^
6:     function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
7:     return new (P || (P = Promise))(function (resolve, reject) {
...and 1 other occurrence
node_modules/node-request-interceptor/lib/XMLHttpRequest/XMLHttpRequest/XMLHttpRequestOverride.js
3: import require$$0 from 'debug?commonjs-proxy';
4:
5: var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
                    ^
6:     function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
7:     return new (P || (P = Promise))(function (resolve, reject) {
...and 1 other occurrence

Edit: This error doesn't occur anymore after node-requrest-interceptor is bundled to ES5 format (mswjs/interceptors#11).

[kettanaito]

I've tried to create a unit test example that asserts a component's behavior that uses axios, but it turns out axios cannot run in Node. Examples I find suggest to use an adapter, or to mock the axios' implementation. Either of those look greatly unreliable to me.