normalize asset size and produce warnings for performance

vigneshshanmugam · sokra · commit d3f2927d7795 · 2016-12-07T17:21:19.000+01:00
diff --git a/lib/performance/EmittedAssetSizeLimitPlugin.js b/lib/performance/EmittedAssetSizeLimitPlugin.js
@@ -11,16 +11,45 @@ function EmittedAssetSizeLimitPlugin(performanceOptions) {
 
 module.exports = EmittedAssetSizeLimitPlugin;
 
+function normalizeAndCompare(sizeLimit, assetSize) {
+	// sizeLimit=maxAssetSize is always expressed in kB
+	// assetSize is expressed in byte size
+	sizeLimit = sizeLimit * 1024;
+	console.log(sizeLimit, assetSize);
+	return sizeLimit < assetSize;
+}
+
+function getJSWarnings(noOfAssets, sizeLimit, assetSize) {
+	var warnings = [];
+	if(normalizeAndCompare(sizeLimit, assetSize)) {
+		if(noOfAssets === 1) {
+			warnings.push(new Error("EmmittedAssetSizeWarning: " + "This asset exceeds " + sizeLimit + "kB. Consider reducing the size for optimal web performance."));
+		} else {
+			warnings.push(new Error("EmmittedAssetSizeWarning: " + "Highlighted chunks are large and are likely to impact web performance. Consider keeping total chunks of page < " +  sizeLimit + "kB"));
+		}
+	}
+	return warnings;
+}
+
 EmittedAssetSizeLimitPlugin.prototype.apply = function(compiler) {
+
+	if(!this.hints) {
+		return;
+	}
+
 	var sizeLimit = this.maxAssetSize;
 	var hints = this.hints;
-	compiler.plugin("after-emit", function(compilation, callback) {
-		for (var asset in compilation.assets) {
-			if (sizeLimit < compilation.assets[asset].size() && hints) {
-				compilation.warnings.push(new Error("EmmittedAssetSizeWarning: " + "This asset exceeds " + sizeLimit + "kB. Consider reducing the size for optimal web performance."));
-			}
-		}
+	var jsRegex = /\.js($|\?)/i;
 
+	compiler.plugin("after-emit", function(compilation, callback) {
+		var assets = Object.keys(compilation.assets);
+		var noOfAssets = assets.length;
+		assets.forEach(function(file) {
+			var assetSize = compilation.assets[file].size();
+			var warnings = jsRegex.test(file) && getJSWarnings(noOfAssets, sizeLimit, assetSize);
+			Array.prototype.push.apply(compilation.warnings, warnings);
+		});
 		callback();
 	});
+
 };
diff --git a/schemas/webpackOptionsSchema.json b/schemas/webpackOptionsSchema.json
@@ -752,7 +752,7 @@
       "additionalProperties": false,
       "properties": {
         "maxAssetSize": {
-          "description": "Filesize limit (in kb) when exceeded, that webpack will provide performance hints",
+          "description": "Filesize limit (in kB) when exceeded, that webpack will provide performance hints",
           "type": "number"
         },
         "hints": {
