MDL-69773 block_section_links: Add an option to display section name
[moodle.git] / babel-plugin-add-module-to-define.js
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1// This file is part of Moodle - http://moodle.org/
2//
3// Moodle is free software: you can redistribute it and/or modify
4// it under the terms of the GNU General Public License as published by
5// the Free Software Foundation, either version 3 of the License, or
6// (at your option) any later version.
7//
8// Moodle is distributed in the hope that it will be useful,
9// but WITHOUT ANY WARRANTY; without even the implied warranty of
10// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11// GNU General Public License for more details.
12//
13// You should have received a copy of the GNU General Public License
14// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
15
16/**
17 * This is a babel plugin to add the Moodle module names to the AMD modules
18 * as part of the transpiling process.
19 *
20 * In addition it will also add a return statement for the default export if the
21 * module is using default exports. This is a highly specific Moodle thing because
22 * we're transpiling to AMD and none of the existing Babel 7 plugins work correctly.
23 *
24 * This will fix the issue where an ES6 module using "export default Foo" will be
25 * transpiled into an AMD module that returns {default: Foo}; Instead it will now
26 * just simply return Foo.
27 *
28 * Note: This means all other named exports in that module are ignored and won't be
29 * exported.
30 *
31 * @copyright 2018 Ryan Wyllie <ryan@moodle.com>
32 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
33 */
34
35"use strict";
f59ac416 36/* eslint-env node */
c53f86d4 37
f59ac416 38module.exports = ({template, types}) => {
c53f86d4 39 const fs = require('fs');
ac1a91bf 40 const path = require('path');
c53f86d4 41 const cwd = process.cwd();
a8109e75 42 const ComponentList = require(path.resolve('GruntfileComponents.js'));
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43
44 /**
45 * Search the list of components that match the given file name
46 * and return the Moodle component for that file, if found.
47 *
48 * Throw an exception if no matching component is found.
49 *
50 * @throws {Error}
51 * @param {string} searchFileName The file name to look for.
52 * @return {string} Moodle component
53 */
54 function getModuleNameFromFileName(searchFileName) {
55 searchFileName = fs.realpathSync(searchFileName);
ac1a91bf 56 const relativeFileName = searchFileName.replace(`${cwd}${path.sep}`, '').replace(/\\/g, '/');
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57 const [componentPath, file] = relativeFileName.split('/amd/src/');
58 const fileName = file.replace('.js', '');
59
60 // Check subsystems first which require an exact match.
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61 const componentName = ComponentList.getComponentFromPath(componentPath);
62 if (componentName) {
63 return `${componentName}/${fileName}`;
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64 }
65
66 // This matches the previous PHP behaviour that would throw an exception
67 // if it couldn't parse an AMD file.
a8109e75 68 throw new Error(`Unable to find module name for ${searchFileName} (${componentPath}::${file}}`);
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69 }
70
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71 /**
72 * This is heavily inspired by the babel-plugin-add-module-exports plugin.
73 * See: https://github.com/59naga/babel-plugin-add-module-exports
74 *
75 * This is used when we detect a module using "export default Foo;" to make
76 * sure the transpiled code just returns Foo directly rather than an object
77 * with the default property (i.e. {default: Foo}).
78 *
79 * Note: This means that we can't support modules that combine named exports
80 * with a default export.
81 *
82 * @param {String} path
83 * @param {String} exportObjectName
84 */
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85 function addModuleExportsDefaults(path, exportObjectName) {
86 const rootPath = path.findParent(path => {
87 return path.key === 'body' || !path.parentPath;
88 });
89
90 // HACK: `path.node.body.push` instead of path.pushContainer(due doesn't work in Plugin.post).
91 // This is hardcoded to work specifically with AMD.
f59ac416 92 rootPath.node.body.push(template(`return ${exportObjectName}.default`)());
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93 }
94
95 return {
96 pre() {
97 this.seenDefine = false;
98 this.addedReturnForDefaultExport = false;
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99 },
100 visitor: {
101 // Plugin ordering is only respected if we visit the "Program" node.
102 // See: https://babeljs.io/docs/en/plugins.html#plugin-preset-ordering
103 //
104 // We require this to run after the other AMD module transformation so
105 // let's visit the "Program" node.
106 Program: {
107 exit(path) {
108 path.traverse({
109 CallExpression(path) {
110 // If we find a "define" function call.
111 if (!this.seenDefine && path.get('callee').isIdentifier({name: 'define'})) {
112 // We only want to modify the first instance of define that we find.
113 this.seenDefine = true;
114 // Get the Moodle component for the file being processed.
115 var moduleName = getModuleNameFromFileName(this.file.opts.filename);
116 // Add the module name as the first argument to the define function.
117 path.node.arguments.unshift(types.stringLiteral(moduleName));
118 // Add a space after the define function in the built file so that previous versions
119 // of Moodle will not try to add the module name to the file when it's being served
120 // by PHP. This forces the regex in PHP to not match for this file.
121 path.node.callee.name = 'define ';
122 }
123
124 // Check for any Object.defineProperty('exports', 'default') calls.
125 if (!this.addedReturnForDefaultExport && path.get('callee').matchesPattern('Object.defineProperty')) {
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126 const [identifier, prop] = path.get('arguments');
127 const objectName = identifier.get('name').node;
128 const propertyName = prop.get('value').node;
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129
130 if ((objectName === 'exports' || objectName === '_exports') && propertyName === 'default') {
131 addModuleExportsDefaults(path, objectName);
132 this.addedReturnForDefaultExport = true;
133 }
134 }
135 },
136 AssignmentExpression(path) {
137 // Check for an exports.default assignments.
138 if (
139 !this.addedReturnForDefaultExport &&
140 (
141 path.get('left').matchesPattern('exports.default') ||
142 path.get('left').matchesPattern('_exports.default')
143 )
144 ) {
145 const objectName = path.get('left.object.name').node;
146 addModuleExportsDefaults(path, objectName);
147 this.addedReturnForDefaultExport = true;
148 }
149 }
150 }, this);
151 }
152 }
153 }
154 };
2c28ba88 155};