/
utils.js
122 lines (101 loc) · 2.62 KB
/
utils.js
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/** @typedef {import("webpack").Compilation["inputFileSystem"] } InputFileSystem */
/** @typedef {import("fs").Stats } Stats */
/**
* @param {InputFileSystem} inputFileSystem
* @param {string} path
* @return {Promise<undefined | Stats>}
*/
function stat(inputFileSystem, path) {
return new Promise((resolve, reject) => {
inputFileSystem.stat(
path,
/**
* @param {null | undefined | NodeJS.ErrnoException} err
* @param {undefined | Stats} stats
*/
// @ts-ignore
(err, stats) => {
if (err) {
reject(err);
return;
}
resolve(stats);
}
);
});
}
/**
* @param {InputFileSystem} inputFileSystem
* @param {string} path
* @return {Promise<string | Buffer>}
*/
function readFile(inputFileSystem, path) {
return new Promise((resolve, reject) => {
inputFileSystem.readFile(
path,
/**
* @param {null | undefined | NodeJS.ErrnoException} err
* @param {undefined | string | Buffer} data
*/
(err, data) => {
if (err) {
reject(err);
return;
}
resolve(/** @type {string | Buffer} */ (data));
}
);
});
}
const notSettled = Symbol(`not-settled`);
/**
* @template T
* @typedef {() => Promise<T>} Task
*/
/**
* Run tasks with limited concurency.
* @template T
* @param {number} limit - Limit of tasks that run at once.
* @param {Task<T>[]} tasks - List of tasks to run.
* @returns {Promise<T[]>} A promise that fulfills to an array of the results
*/
function throttleAll(limit, tasks) {
if (!Number.isInteger(limit) || limit < 1) {
throw new TypeError(
`Expected \`limit\` to be a finite number > 0, got \`${limit}\` (${typeof limit})`
);
}
if (
!Array.isArray(tasks) ||
!tasks.every((task) => typeof task === `function`)
) {
throw new TypeError(
`Expected \`tasks\` to be a list of functions returning a promise`
);
}
return new Promise((resolve, reject) => {
const result = Array(tasks.length).fill(notSettled);
const entries = tasks.entries();
const next = () => {
const { done, value } = entries.next();
if (done) {
const isLast = !result.includes(notSettled);
if (isLast) {
resolve(/** @type{T[]} **/ (result));
}
return;
}
const [index, task] = value;
/**
* @param {T} x
*/
const onFulfilled = (x) => {
result[index] = x;
next();
};
task().then(onFulfilled, reject);
};
Array(limit).fill(0).forEach(next);
});
}
module.exports = { stat, readFile, throttleAll };