@graphql-hive/core/esm/circuit-breaker/semaphore.js

function semaphore(count) {
    const resolvers = [];
    let counter = count;
    const sem = {
        take,
        release,
        test,
    };
    Object.defineProperty(sem, 'count', {
        get: _ => counter,
        enumerable: true,
    });
    return sem;
    function take(timeout) {
        if (counter > 0) {
            --counter;
            return Promise.resolve(release);
        }
        return new Promise((resolve, reject) => {
            resolvers.push(_ => {
                --counter;
                resolve(release);
            });
            if (timeout) {
                setTimeout(_ => {
                    resolvers.shift();
                    const err = new Error(`Timed out after ${timeout}ms`);
                    err.code = 'ETIMEDOUT';
                    reject(err);
                }, timeout);
            }
        });
    }
    function release() {
        counter++;
        if (resolvers.length > 0) {
            resolvers.shift()();
        }
    }
    function test() {
        if (counter < 1)
            return false;
        return take() && true;
    }
}
export default semaphore;