webpack/lib/optimize/UglifyJsPlugin.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jade, coffee, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
var SourceMapConsumer = require("webpack-core/lib/source-map").SourceMapConsumer;
var SourceMapSource = require("webpack-core/lib/SourceMapSource");
var RequestShortener = require("../RequestShortener");
var uglify = require("uglify-js");

function UglifyJsPlugin(options) {
	if(typeof options !== "object") options = {};
	if(typeof options.compressor !== "undefined") {
		options.compress = options.compressor;
	}
	this.options = options;
}
module.exports = UglifyJsPlugin;
UglifyJsPlugin.prototype.apply = function(compiler) {
	var options = this.options;
	var requestShortener = new RequestShortener(compiler.context);
	compiler.plugin("compilation", function(compilation) {
		compilation.plugin("build-module", function(module) {
			// to get detailed location info about errors
			module.useSourceMap = true;
		});
		compilation.plugin("optimize-chunk-assets", function(chunks, callback) {
			var files = [];
			chunks.forEach(function(chunk) {
				chunk.files.forEach(function(file) {
					files.push(file);
				});
			});
			compilation.additionalChunkAssets.forEach(function(file) {
				files.push(file);
			});
			files.forEach(function(file) {
				if(!/\.js$/i.test(file)) {
					// UglifyJs only applies to javascript
					return;
				}
				var oldWarnFunction = uglify.AST_Node.warn_function;
				var warnings = [];
				try {
					var asset = compilation.assets[file];
					var input = asset.source();
					if(asset.__UglifyJsPlugin) {
						compilation.assets[file] = asset.__UglifyJsPlugin;
						return;
					}
					var inputSourceMap = asset.map();
					var sourceMap = new SourceMapConsumer(inputSourceMap);
					uglify.AST_Node.warn_function = function(warning) {
						var match = /\[.+:([0-9]+),([0-9]+)\]/.exec(warning);
						var line = +match[1];
						var column = +match[2];
						var original = sourceMap.originalPositionFor({
							line: line,
							column: column
						});
						if(!original || !original.source || original.source === file) return;
						warnings.push(warning.replace(/\[.+:([0-9]+),([0-9]+)\]/, "") + 
							"[" + requestShortener.shorten(original.source) + ":" + original.line + "," + original.column + "]");
					};
					var ast = uglify.parse(input, {
						filename: file
					});
					ast.figure_out_scope()
					if(options.compress !== false) {
						var compress = uglify.Compressor(options.compress);
						ast = ast.transform(compress);
						ast.figure_out_scope();
						if(options.mangle !== false) {
							ast.compute_char_frequency(options.mangle || {});
							ast.mangle_names(options.mangle || {});
						}
					}
					var map = null;
					map = uglify.SourceMap({
						file: file,
						root: ""
					});
					var output = {};
					output.comments = options.comments || /^\**!|@preserve|@license/;
					output.beautify = options.beautify;
					for(var k in options.output) {
						output[k] = options.output[k];
					}
					output.source_map = map;
					var stream = uglify.OutputStream(output);
					ast.print(stream);
					map = map + "";
					stream = stream + "";
					asset.__UglifyJsPlugin = compilation.assets[file] = new SourceMapSource(stream, file, map, input, inputSourceMap);
					if(warnings.length > 0) {
						compilation.warnings.push(new Error(file + " from UglifyJs\n" + warnings.join("\n")));
					}
				} catch(err) {
					if(err.line) {
						var original = sourceMap.originalPositionFor({
							line: err.line,
							column: err.col
						});
						if(original && original.source) {
							compilation.errors.push(new Error(file + " from UglifyJs\n" + err.message + " [" + requestShortener.shorten(original.source) + ":" + original.line + "," + original.column + "]"));
						} else {
							compilation.errors.push(new Error(file + " from UglifyJs\n" + err.message + " [" + file + ":" + err.line + "," + err.col + "]"));
						}
					} else
						compilation.errors.push(new Error(file + " from UglifyJs\n" + err.stack));
				} finally {
					uglify.AST_Node.warn_function = oldWarnFunction;
				}
			});
			callback();
		});
		compilation.plugin("normal-module-loader", function(context) {
			context.minimize = true;
		});
	});
};