flow like the river

BACK_BACK/node_modules/htmlnano/lib/modules/minifyJs.js

@@ -0,0 +1,109 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = minifyJs;
+
+var _terser = _interopRequireDefault(require("terser"));
+
+var _removeRedundantAttributes = require("./removeRedundantAttributes");
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+/** Minify JS with Terser */
+function minifyJs(tree, options, terserOptions) {
+  let promises = [];
+  tree.walk(node => {
+    if (node.tag && node.tag === 'script') {
+      const nodeAttrs = node.attrs || {};
+      const mimeType = nodeAttrs.type || 'text/javascript';
+
+      if (_removeRedundantAttributes.redundantScriptTypes.has(mimeType) || mimeType === 'module') {
+        promises.push(processScriptNode(node, terserOptions));
+      }
+    }
+
+    if (node.attrs) {
+      promises = promises.concat(processNodeWithOnAttrs(node, terserOptions));
+    }
+
+    return node;
+  });
+  return Promise.all(promises).then(() => tree);
+}
+
+function stripCdata(js) {
+  const leftStrippedJs = js.replace(/\/\/\s*<!\[CDATA\[/, '').replace(/\/\*\s*<!\[CDATA\[\s*\*\//, '');
+
+  if (leftStrippedJs === js) {
+    return js;
+  }
+
+  const strippedJs = leftStrippedJs.replace(/\/\/\s*\]\]>/, '').replace(/\/\*\s*\]\]>\s*\*\//, '');
+  return leftStrippedJs === strippedJs ? js : strippedJs;
+}
+
+function processScriptNode(scriptNode, terserOptions) {
+  let js = (scriptNode.content || []).join('').trim();
+
+  if (!js) {
+    return scriptNode;
+  } // Improve performance by avoiding calling stripCdata again and again
+
+
+  let isCdataWrapped = false;
+
+  if (js.includes('CDATA')) {
+    const strippedJs = stripCdata(js);
+    isCdataWrapped = js !== strippedJs;
+    js = strippedJs;
+  }
+
+  return _terser.default.minify(js, terserOptions).then(result => {
+    if (result.error) {
+      throw new Error(result.error);
+    }
+
+    if (result.code === undefined) {
+      return;
+    }
+
+    let content = result.code;
+
+    if (isCdataWrapped) {
+      content = '/*<![CDATA[*/' + content + '/*]]>*/';
+    }
+
+    scriptNode.content = [content];
+  });
+}
+
+function processNodeWithOnAttrs(node, terserOptions) {
+  const jsWrapperStart = 'function _(){';
+  const jsWrapperEnd = '}';
+  const promises = [];
+
+  for (const attrName of Object.keys(node.attrs || {})) {
+    if (!attrName.startsWith('on')) {
+      continue;
+    } // For example onclick="return false" is valid,
+    // but "return false;" is invalid (error: 'return' outside of function)
+    // Therefore the attribute's code should be wrapped inside function:
+    // "function _(){return false;}"
+
+
+    let wrappedJs = jsWrapperStart + node.attrs[attrName] + jsWrapperEnd;
+
+    let promise = _terser.default.minify(wrappedJs, terserOptions).then(({
+      code
+    }) => {
+      let minifiedJs = code.substring(jsWrapperStart.length, code.length - jsWrapperEnd.length);
+      node.attrs[attrName] = minifiedJs;
+    });
+
+    promises.push(promise);
+  }
+
+  return promises;
+}