1 files changed, 193 insertions, 0 deletions
diff --git a/build/tasks/lib/compareSize.js b/build/tasks/lib/compareSize.js
new file mode 100644
index 000000000..729bb37f2
--- /dev/null
+++ b/build/tasks/lib/compareSize.js
@@ -0,0 +1,193 @@
+import fs from "node:fs/promises";
+import { promisify } from "node:util";
+import zlib from "node:zlib";
+import { exec as nodeExec } from "node:child_process";
+import chalk from "chalk";
+import isCleanWorkingDir from "./isCleanWorkingDir.js";
+
+const VERSION = 1;
+const lastRunBranch = " last run";
+
+const gzip = promisify( zlib.gzip );
+const exec = promisify( nodeExec );
+
+async function getBranchName() {
+	const { stdout } = await exec( "git rev-parse --abbrev-ref HEAD" );
+	return stdout.trim();
+}
+
+async function getCommitHash() {
+	const { stdout } = await exec( "git rev-parse HEAD" );
+	return stdout.trim();
+}
+
+function getBranchHeader( branch, commit ) {
+	let branchHeader = branch.trim();
+	if ( commit ) {
+		branchHeader = chalk.bold( branchHeader ) + chalk.gray( ` @${ commit }` );
+	} else {
+		branchHeader = chalk.italic( branchHeader );
+	}
+	return branchHeader;
+}
+
+async function getCache( loc ) {
+	let cache;
+	try {
+		const contents = await fs.readFile( loc, "utf8" );
+		cache = JSON.parse( contents );
+	} catch ( err ) {
+		return {};
+	}
+
+	const lastRun = cache[ lastRunBranch ];
+	if ( !lastRun || !lastRun.meta || lastRun.meta.version !== VERSION ) {
+		console.log( "Compare cache version mismatch. Rewriting..." );
+		return {};
+	}
+	return cache;
+}
+
+function cacheResults( results ) {
+	const files = Object.create( null );
+	results.forEach( function( result ) {
+		files[ result.filename ] = {
+			raw: result.raw,
+			gz: result.gz
+		};
+	} );
+	return files;
+}
+
+function saveCache( loc, cache ) {
+
+	// Keep cache readable for manual edits
+	return fs.writeFile( loc, JSON.stringify( cache, null, "  " ) + "\n" );
+}
+
+function compareSizes( existing, current, padLength ) {
+	if ( typeof current !== "number" ) {
+		return chalk.grey( `${ existing }`.padStart( padLength ) );
+	}
+	const delta = current - existing;
+	if ( delta > 0 ) {
+		return chalk.red( `+${ delta }`.padStart( padLength ) );
+	}
+	return chalk.green( `${ delta }`.padStart( padLength ) );
+}
+
+function sortBranches( a, b ) {
+	if ( a === lastRunBranch ) {
+		return 1;
+	}
+	if ( b === lastRunBranch ) {
+		return -1;
+	}
+	if ( a < b ) {
+		return -1;
+	}
+	if ( a > b ) {
+		return 1;
+	}
+	return 0;
+}
+
+export async function compareSize( { cache = ".sizecache.json", files } = {} ) {
+	if ( !files || !files.length ) {
+		throw new Error( "No files specified" );
+	}
+
+	const branch = await getBranchName();
+	const commit = await getCommitHash();
+	const sizeCache = await getCache( cache );
+
+	let rawPadLength = 0;
+	let gzPadLength = 0;
+	const results = await Promise.all(
+		files.map( async function( filename ) {
+
+			let contents = await fs.readFile( filename, "utf8" );
+
+			// Remove the short SHA and .dirty from comparisons.
+			// The short SHA so commits can be compared against each other
+			// and .dirty to compare with the existing branch during development.
+			const sha = /jQuery v\d+.\d+.\d+(?:-\w+)?(?:\+slim\.|\+)?([^ \.]+(?:\.dirty)?)?/.exec( contents )[ 1 ];
+			contents = contents.replace( new RegExp( sha, "g" ), "" );
+
+			const size = Buffer.byteLength( contents, "utf8" );
+			const gzippedSize = ( await gzip( contents ) ).length;
+
+			// Add one to give space for the `+` or `-` in the comparison
+			rawPadLength = Math.max( rawPadLength, size.toString().length + 1 );
+			gzPadLength = Math.max( gzPadLength, gzippedSize.toString().length + 1 );
+
+			return { filename, raw: size, gz: gzippedSize };
+		} )
+	);
+
+	const sizeHeader = "raw".padStart( rawPadLength ) +
+		"gz".padStart( gzPadLength + 1 ) +
+		" Filename";
+
+	const sizes = results.map( function( result ) {
+		const rawSize = result.raw.toString().padStart( rawPadLength );
+		const gzSize = result.gz.toString().padStart( gzPadLength );
+		return `${ rawSize } ${ gzSize } ${ result.filename }`;
+	} );
+
+	const comparisons = Object.keys( sizeCache ).sort( sortBranches ).map( function( branch ) {
+		const meta = sizeCache[ branch ].meta || {};
+		const commit = meta.commit;
+
+		const files = sizeCache[ branch ].files;
+		const branchSizes = Object.keys( files ).map( function( filename ) {
+			const branchResult = files[ filename ];
+			const compareResult = results.find( function( result ) {
+				return result.filename === filename;
+			} ) || {};
+
+			const compareRaw = compareSizes( branchResult.raw, compareResult.raw, rawPadLength );
+			const compareGz = compareSizes( branchResult.gz, compareResult.gz, gzPadLength );
+			return `${ compareRaw } ${ compareGz } ${ filename }`;
+		} );
+
+		return [
+			"", // New line before each branch
+			getBranchHeader( branch, commit ),
+			sizeHeader,
+			...branchSizes
+		].join( "\n" );
+	} );
+
+	const output = [
+		"", // Opening new line
+		chalk.bold( "Sizes" ),
+		sizeHeader,
+		...sizes,
+		...comparisons,
+		"" // Closing new line
+	].join( "\n" );
+
+	console.log( output );
+
+	// Always save the last run
+	// Save version under last run
+	sizeCache[ lastRunBranch ] = {
+		meta: { version: VERSION },
+		files: cacheResults( results )
+	};
+
+	// Only save cache for the current branch
+	// if the working directory is clean.
+	if ( await isCleanWorkingDir() ) {
+		sizeCache[ branch ] = {
+			meta: { commit },
+			files: cacheResults( results )
+		};
+		console.log( `Saved cache for ${ branch }.` );
+	}
+
+	await saveCache( cache, sizeCache );
+
+	return results;
+}