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feat(ModuleImporter): implement import module compatible with bundlers (
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nrauschcom committed Oct 8, 2021
1 parent 872e7a5 commit d399a28
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Showing 2 changed files with 84 additions and 5 deletions.
9 changes: 4 additions & 5 deletions src/client/actions/ActionsManager.js
@@ -1,16 +1,15 @@
'use strict';

const fs = require('node:fs');
const ModuleImporter = require('../../util/ModuleImporter');

class ActionsManager {
constructor(client) {
this.client = client;

const files = fs.readdirSync(__dirname);
const modules = ModuleImporter.import('./client/actions', ['Action.js', 'ActionsManager.js']);

for (const file of files) {
if (['Action.js', 'ActionsManager.js'].includes(file)) continue;
this.register(require(`./${file}`));
for (const module of modules) {
this.register(module);
}
}

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80 changes: 80 additions & 0 deletions src/util/ModuleImporter.js
@@ -0,0 +1,80 @@
'use strict';

const fs = require('node:fs');
const path = require('node:path');

/**
* The ModuleImporter helper class is used to import local files, by using the bundler or file system, whichever is
* needed in the current build.
*
* @private
*/
class ModuleImporter extends null {
/**
* This method is used to import a variable number of files in a specific directory and is built to also work with
* webpack and potentially other bundlers.
*
* @param {string} pathToDirectory the path to the searched directory (relative to the `src` directory)
* @param {string[]} [excludedFiles=[]] an array of files which are excluded from the import
*
* @returns {unknown[]} an array of dynamically imported modules
*/
static import(pathToDirectory, excludedFiles = []) {
pathToDirectory = path.normalize(pathToDirectory);

let moduleMap;

if (typeof __webpack_require__ === 'function') {
moduleMap = this.importWebpack(pathToDirectory);
} else {
moduleMap = this.importFilesystem(pathToDirectory);
}

const requiredModules = [];
for (const [fileName, requireFunction] of moduleMap.entries()) {
if (excludedFiles.includes(path.basename(fileName))) continue;
requiredModules.push(requireFunction());
}

return requiredModules;
}

/**
* Helper function to import all modules in a given directory via file system.
*
* @param {string} pathToDirectory the path to the searched directory (relative to the `src` directory)
* @returns {Map<string, Function>} a map of resolved file names to their require function
*
* @private
*/
static importFilesystem(pathToDirectory) {
const basePath = path.resolve(__dirname, '..', pathToDirectory);
const files = fs.readdirSync(basePath);
// Require Function is returned for lazy evaluation
return new Map(files.map(file => [file, () => require(path.join(basePath, file))]));
}

/**
* Helper function to import all modules in a given directory via webpack.context.
*
* @param {string} pathToDirectory the path to the searched directory (relative to the `src` directory)
* @returns {Map<string, Function>} a map of resolved file names to their require function
*
* @private
*/
static importWebpack(pathToDirectory) {
// The "function" `require.context` is actually evaluated at build/bundling time, and needs to be called with
// literals because of that. By building a context of '..' we actually cover the whole codebase and can
// dynamically import any subdirectory. When not using webpack, the following line is never evaluated.
const context = require.context('..', true, /\.js$/);

const files = context
.keys()
// We have all files in our context, so now we filter the files in the correct directory
.filter(file => path.normalize(file).startsWith(pathToDirectory));

return new Map(files.map(file => [file, () => context(file)]));
}
}

module.exports = ModuleImporter;

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