Add compressor options

src/index.js

@@ -44,6 +44,31 @@ const toTerserLiteral = (value, name) => {
 	// default: behaviour from Terser (@prefix=1 produces expression/literal, unprefixed=1 produces string literal):
 };
 
+// Normalize Terser options from microbundle's relaxed JSON format (mutates argument in-place)
+function normalizeMinifyOptions(minifyOptions) {
+	const mangle = minifyOptions.mangle || (minifyOptions.mangle = {});
+	let properties = mangle.properties;
+
+	// allow top-level "properties" key to override mangle.properties (including {properties:false}):
+	if (minifyOptions.properties != null) {
+		properties = mangle.properties =
+			minifyOptions.properties &&
+			Object.assign(properties, minifyOptions.properties);
+	}
+
+	// allow previous format ({ mangle:{regex:'^_',reserved:[]} }):
+	if (minifyOptions.regex || minifyOptions.reserved) {
+		if (!properties) properties = mangle.properties = {};
+		properties.regex = properties.regex || minifyOptions.regex;
+		properties.reserved = properties.reserved || minifyOptions.reserved;
+	}
+
+	if (properties) {
+		if (properties.regex) properties.regex = new RegExp(properties.regex);
+		properties.reserved = [].concat(properties.reserved || []);
+	}
+}
+
 // Parses values of the form "$=jQuery,React=react" into key-value object pairs.
 const parseMappingArgument = (globalStrings, processValue) => {
 	const globals = {};
@@ -387,7 +412,9 @@ function createConfig(options, entry, format, writeMeta) {
 	// let rollupName = safeVariableName(basename(entry).replace(/\.js$/, ''));
 
 	let nameCache = {};
-	let mangleOptions = options.pkg.mangle || false;
+	const bareNameCache = nameCache;
+	// Support "minify" field and legacy "mangle" field via package.json:
+	let minifyOptions = options.pkg.minify || options.pkg.mangle || {};
 
 	const useTypescript = extname(entry) === '.ts' || extname(entry) === '.tsx';
 
@@ -400,10 +427,22 @@ function createConfig(options, entry, format, writeMeta) {
 			nameCache = JSON.parse(
 				fs.readFileSync(resolve(options.cwd, 'mangle.json'), 'utf8'),
 			);
+			// mangle.json can contain a "minify" field, same format as the pkg.mangle:
+			if (nameCache.minify) {
+				minifyOptions = Object.assign(
+					{},
+					minifyOptions || {},
+					nameCache.minify,
+				);
+			}
 		} catch (e) {}
 	}
 	loadNameCache();
 
+	normalizeMinifyOptions(minifyOptions);
+
+	if (nameCache === bareNameCache) nameCache = null;
+
 	let shebang;
 
 	let config = {
@@ -539,28 +578,22 @@ function createConfig(options, entry, format, writeMeta) {
 						terser({
 							sourcemap: true,
 							output: { comments: false },
-							compress: {
-								keep_infinity: true,
-								pure_getters: true,
-								global_defs: defines,
-								passes: 10,
-							},
+							compress: Object.assign(
+								{
+									keep_infinity: true,
+									pure_getters: true,
+									global_defs: defines,
+									passes: 10,
+								},
+								minifyOptions.compress || {},
+							),
 							warnings: true,
 							ecma: 5,
 							toplevel: format === 'cjs' || format === 'es',
-							mangle: {
-								properties: mangleOptions
-									? {
-											regex: mangleOptions.regex
-												? new RegExp(mangleOptions.regex)
-												: null,
-											reserved: mangleOptions.reserved || [],
-									  }
-									: false,
-							},
+							mangle: Object.assign({}, minifyOptions.mangle || {}),
 							nameCache,
 						}),
-						mangleOptions && {
+						nameCache && {
 							// before hook
 							options: loadNameCache,
 							// after hook