103 lines
3.5 KiB
JavaScript
103 lines
3.5 KiB
JavaScript
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"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.default = minifyJs;
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var _helpers = require("../helpers.cjs");
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var _removeRedundantAttributes = require("./removeRedundantAttributes.cjs");
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/** Minify JS with Terser */
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async function minifyJs(tree, options, terserOptions) {
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const terser = await (0, _helpers.optionalImport)('terser');
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if (!terser) return tree;
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let promises = [];
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tree.walk(node => {
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const nodeAttrs = node.attrs || {};
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/**
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* Skip SRI
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*
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* If the input <script /> has an SRI attribute, it means that the original <script /> could be trusted,
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* and should not be altered anymore.
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*
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* htmlnano is exactly an MITM that SRI is designed to protect from. If htmlnano or its dependencies get
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* compromised and introduces malicious code, then it is up to the original SRI to protect the end user.
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*
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* So htmlnano will simply skip <script /> that has SRI.
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* If developers do trust htmlnano, they should generate SRI after htmlnano modify the <script />.
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*/
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if ('integrity' in nodeAttrs) {
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return node;
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}
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if (node.tag && node.tag === 'script') {
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const mimeType = nodeAttrs.type || 'text/javascript';
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if (_removeRedundantAttributes.redundantScriptTypes.has(mimeType) || mimeType === 'module') {
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promises.push(processScriptNode(node, terserOptions, terser));
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}
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}
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if (node.attrs) {
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promises = promises.concat(processNodeWithOnAttrs(node, terserOptions, terser));
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}
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return node;
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});
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return Promise.all(promises).then(() => tree);
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}
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function stripCdata(js) {
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const leftStrippedJs = js.replace(/\/\/\s*<!\[CDATA\[/, '').replace(/\/\*\s*<!\[CDATA\[\s*\*\//, '');
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if (leftStrippedJs === js) {
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return js;
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}
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const strippedJs = leftStrippedJs.replace(/\/\/\s*\]\]>/, '').replace(/\/\*\s*\]\]>\s*\*\//, '');
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return leftStrippedJs === strippedJs ? js : strippedJs;
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}
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function processScriptNode(scriptNode, terserOptions, terser) {
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let js = (scriptNode.content || []).join('').trim();
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if (!js) {
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return scriptNode;
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}
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// Improve performance by avoiding calling stripCdata again and again
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let isCdataWrapped = false;
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if (js.includes('CDATA')) {
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const strippedJs = stripCdata(js);
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isCdataWrapped = js !== strippedJs;
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js = strippedJs;
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}
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return terser.minify(js, terserOptions).then(result => {
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if (result.error) {
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throw new Error(result.error);
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}
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if (result.code === undefined) {
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return;
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}
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let content = result.code;
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if (isCdataWrapped) {
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content = '/*<![CDATA[*/' + content + '/*]]>*/';
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}
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scriptNode.content = [content];
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});
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}
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function processNodeWithOnAttrs(node, terserOptions, terser) {
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const jsWrapperStart = 'a=function(){';
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const jsWrapperEnd = '};a();';
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const promises = [];
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for (const attrName of Object.keys(node.attrs || {})) {
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if (!(0, _helpers.isEventHandler)(attrName)) {
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continue;
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}
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// For example onclick="return false" is valid,
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// but "return false;" is invalid (error: 'return' outside of function)
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// Therefore the attribute's code should be wrapped inside function:
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// "function _(){return false;}"
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let wrappedJs = jsWrapperStart + node.attrs[attrName] + jsWrapperEnd;
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let promise = terser.minify(wrappedJs, terserOptions).then(({
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code
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}) => {
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let minifiedJs = code.substring(jsWrapperStart.length, code.length - jsWrapperEnd.length);
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node.attrs[attrName] = minifiedJs;
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});
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promises.push(promise);
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}
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return promises;
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}
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