vtils/_cjs/utils/asyncLimit.js

一个面向业务的 JavaScript/TypeScript 实用程序库。

"use strict";

exports.__esModule = true;
exports.asyncLimit = asyncLimit;
/**
 * 异步函数并行执行限制。
 *
 * @param asyncFn 异步函数
 * @param options 选项
 */
function asyncLimit(asyncFn, options) {
  if (options === void 0) {
    options = {};
  }
  var _options = options,
    _options$concurrency = _options.concurrency,
    concurrency = _options$concurrency === void 0 ? 1 : _options$concurrency;
  var queue = [];
  var activeCount = 0;
  var call = function call() {
    for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
      args[_key] = arguments[_key];
    }
    return new Promise(function (resolve) {
      queue.push([args, resolve]);
      run();
    });
  };
  var run = function run() {
    if (activeCount < concurrency && queue.length) {
      activeCount++;
      var _ref = queue.shift(),
        _args = _ref[0],
        _resolve = _ref[1];
      var _res = asyncFn.apply(void 0, _args);
      _resolve(_res);
      _res.then(next, next);
    }
  };
  var next = function next() {
    activeCount--;
    run();
  };
  return call;
}