lib/index.esm.js
function race(iterable) {
    var C = this;
    var capability = newPromiseCapability(C);
    var reject = capability.reject;
    var result = _perform(function () {
      _forOf(iterable, false, function (promise) {
        C.resolve(promise).then(capability.resolve, reject);
      });
    });
    if (result.e) reject(result.v);
    return capability.promise;
  }
function race(iterable) {
    var C = this;
    var capability = newPromiseCapability(C);
    var reject = capability.reject;
    var result = _perform(function () {
      _forOf(iterable, false, function (promise) {
        C.resolve(promise).then(capability.resolve, reject);
      });
    });
    if (result.e) reject(result.v);
    return capability.promise;
  }
25.4.4.4 Promise.race(iterable)