Build: replace grunt tasks with npm scripts

Includes:

- **lint**: lint all code using new eslint flat config
- **build**: build using rollup, minify using uglify, process for dist
- **npmcopy**: copy some node module files to the external folder
- **start**: watch source files and rebuild on changes using rollup.watch

Also:
- Update the build function in the release script to use the new build
- Update CONTRIBUTING.md and README.md with new scripts
- Confirm the min file was identical to the main branch build, aside from the version update.
- Keep uglify-js at 3.9.4, which is the last version that officially
  supported the ie8 argument, which we need for ie9

Closes jquerygh-512

Author: timmywil

.eslintignore

@@ -70,8 +70,8 @@ jobs:
       - name: Install dependencies
         run: npm install
 
-      - name: Build
-        run: npm run build
+      - name: Pretest script
+        run: npm run pretest
 
       - name: Test
         run: |

.eslintrc-browser.json

@@ -55,8 +55,8 @@ jobs:
       - name: Install dependencies
         run: npm install
 
-      - name: Build
-        run: npm run build
+      - name: Pretest script
+        run: npm run pretest
 
       - name: Test
         run: |

.eslintrc-node.json

@@ -8,11 +8,9 @@ CDN
 /*.html
 .DS_Store
 .sizecache.json
+.eslintcache
 
-# Ignore everything in dist folder except for eslint config
-/dist/*
-!/dist/.eslintrc.json
-
+/dist
 /external
 /node_modules
 

.eslintrc.json

@@ -68,11 +68,8 @@ See: [jQuery Core Style Guide](http://docs.jquery.com/JQuery_Core_Style_Guidelin
 
 To test the plugin you will need:
 
-* Some kind of localhost server(any will do)
 * Node.js
 * NPM (comes with the latest version of Node.js)
-* Grunt (install with: `npm install grunt -g`)
-
 
 ### Build a Local Copy of the plugin
 
@@ -108,13 +105,19 @@ Get in the habit of pulling in the "upstream" `main` branch to stay up to date a
 $ git pull upstream main
 ```
 
-Run the Grunt tools:
+Run the build and rebuild when source files change:
+
+```bash
+$ npm start
+```
+
+In another terminal, run the test server:
 
 ```bash
-$ grunt && grunt watch
+$ npm run test:server
 ```
 
-Now open the jQuery test suite in a browser at http://localhost/test. If there is a port, be sure to include it.
+Now open the jQuery test suite in a browser at http://localhost:3000/test/.
 
 Success! You just built and tested jQuery!
 

.github/workflows/browserstack-3.x.yml

@@ -89,21 +89,12 @@ Build and run tests:
 ====================================================
 
 ## Build with `npm` commands
-```sh
-$ git clone git://github.com/jquery/jquery-migrate.git
-$ cd jquery-migrate
-$ npm install
-$ npm run build
-```
-
-## Build with [`grunt`](http://gruntjs.com/)
 
 ```sh
 $ git clone git://github.com/jquery/jquery-migrate.git
 $ cd jquery-migrate
 $ npm install
-$ npm install -g grunt-cli
-$ grunt build
+$ npm run build
 ```
 
 ### Run tests
@@ -115,5 +106,7 @@ $ npm test
 ### Or
 
 ```sh
-$ grunt test
+$ npm run test:server
 ```
+
+and open http://localhost:3000/test/ in your browser.

.github/workflows/browserstack-git.yml

@@ -3,8 +3,6 @@
  * JQuery Migrate Plugin Release Management
  */
 
-"use strict";
-
 // Debugging variables
 var	dryrun = false,
 	skipRemote = false;
@@ -14,6 +12,7 @@ import child from "child_process";
 import path from "path";
 import chalk from "chalk";
 import enquirer from "enquirer";
+import { build } from "./tasks/build";
 
 var releaseVersion,
 	nextVersion,
@@ -27,7 +26,6 @@ var releaseVersion,
 
 	// Windows needs the .cmd version but will find the non-.cmd
 	// On Windows, also ensure the HOME environment variable is set
-	gruntCmd = process.platform === "win32" ? "grunt.cmd" : "grunt",
 	npmCmd = process.platform === "win32" ? "npm.cmd" : "npm",
 
 	readmeFile = "README.md",
@@ -40,10 +38,10 @@ var releaseVersion,
 steps(
 	initialize,
 	checkGitStatus,
-	gruntBuild,
+	buildRelease,
 	updateVersions,
 	tagReleaseVersion,
-	gruntBuild,
+	buildRelease,
 	makeReleaseCopies,
 	publishToNPM,
 	setNextVersion,
@@ -64,7 +62,7 @@ function initialize( next ) {
 
 	// -r skip remote mode, no remote commands are executed
 	// (git push, npm publish, cdn copy)
-	// Reset with `git reset --hard HEAD~2 && git tag -d (version) && grunt`
+	// Reset with `git reset --hard HEAD~2 && git tag -d (version) && npm run build`
 	if ( process.argv[ 2 ] === "-r" ) {
 		process.argv.shift();
 		skipRemote = true;
@@ -153,14 +151,9 @@ function updateVersions( next ) {
 	next();
 }
 
-function gruntBuild( next ) {
-	exec( gruntCmd, [], function( error, stdout, stderr ) {
-		if ( error ) {
-			die( error + stderr );
-		}
-		log( stdout || "(no output)" );
-		next();
-	} );
+async function buildRelease( next ) {
+	await build( { version: releaseVersion } );
+	next();
 }
 
 function makeReleaseCopies( next ) {