websnacks/src/utils.ts

73 lines
2 KiB
TypeScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
*/
import { promises as fs } from "fs";
import * as path from "path";
/**
* Recursively walk a directory, returning the files it finds.
*
* @param dirPath Path to the directory to walk.
*
* @return Generator that yields the files found while walking the directory.
*/
export const walkDir = async function* (
dirPath: string
): AsyncGenerator<string> {
const dirEnts = await fs.readdir(dirPath, { withFileTypes: true });
for (const dirEnt of dirEnts) {
if (dirEnt.isDirectory()) {
yield* walkDir(path.join(dirPath, dirEnt.name));
}
if (dirEnt.isFile()) {
yield path.join(dirPath, dirEnt.name);
}
}
};
/**
* Purge cached versions of a node module and all of its dependencies from the
* global require cache, ensuring that future imports reload the module from
* disk.
*
* @param modName Name of the module to purge from the require cache.
*/
export const purgeModuleAndDepsFromCache = (modName: string): void => {
const modPath = require.resolve(modName);
if (modPath == null) {
return;
}
const mod = require.cache[modPath];
if (mod == null) {
return;
}
for (const child of mod.children) {
purgeModuleAndDepsFromCache(child.id);
}
delete require.cache[modPath];
};
export type Flattenable<T> = Array<T | Flattenable<T>>;
const flatDeepRec = <T>(arr: Flattenable<T>, d: number): T[] => {
if (d <= 0) {
return arr.slice() as T[];
}
let acc = [] as T[];
for (const val of arr) {
acc = acc.concat(Array.isArray(val) ? flatDeepRec(arr, d - 1) : val);
}
return acc;
};
/**
* Flatten an arbitrarily-deeply nested array into a flat array.
*
* @param arr Array to flatten.
*
* @return Flattened array.
*/
export const flatDeep = <T>(arr: Flattenable<T>): T[] => flatDeepRec(arr, 1);