Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 | 40x 40x 40x 67x 67x 61x 61x 6x 67x 67x 6x 61x 5x 40x 40x 40x 67x 67x 67x 62x 67x 40x 40x 36x 5x | class Semaphore {
private maxConcurrency: number;
private currentConcurrency: number;
private queue: (() => void)[];
constructor(maxConcurrency: number) {
this.maxConcurrency = maxConcurrency;
this.currentConcurrency = 0;
this.queue = [];
}
async acquire() {
return new Promise<void>((resolve) => {
if (this.currentConcurrency < this.maxConcurrency) {
this.currentConcurrency++;
resolve();
} else {
this.queue.push(resolve);
}
});
}
release() {
const resolve = this.queue.shift();
if (resolve) {
resolve();
} else {
this.currentConcurrency--;
}
}
}
const promiseLimit = async <T>(
n: number,
list: (() => Promise<T>)[]
): Promise<T[]> => {
const semaphore = new Semaphore(n);
const results: T[] = [];
const limitedFn = async (
fn: () => Promise<T>,
index: number
): Promise<void> => {
await semaphore.acquire();
try {
const result = await fn();
results[index] = result;
} finally {
semaphore.release();
}
};
const promises = list.map(limitedFn);
await Promise.all(promises);
return results;
};
export default promiseLimit;
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