'use strict'; var promise = require('./promise'); var TimeoutError = require('./TimeoutError');


Provides helper methods for delaying fulfillment and guarding against indefinitely pending promises or thenables.

function timer(ms, func) { var ref; if (ms) { ref = setTimeout(func, ms); } else { ref = setImmediate(func); } return function abortTimer() { if (ms) { clearTimeout(ref); } else { clearImmediate(ref); } }; }

delay(milliseconds, x)

Returns a Promise instance which is fulfilled after at least milliseconds have passed.

If x is a thenable it is first assimilated into a promise.

If x is a Promise instance or a thenable, the clock won't start running until it has fulfilled. The returned promise will be fulfilled with the same value, or x if it was not a Promise instance or thenable.

If x rejects, the returned promise will be rejected with the same rejection reason. Note that the rejection propagation is not delayed.

To start the clock straight away, without waiting for x to be fulfilled, you could use:

function delay(milliseconds, x) { return promise.Promise.from(x).then(function(value) { return new promise.Promise(function(resolve) { return timer(milliseconds, function() { resolve(value); }); }); }); } exports.delay = delay;

timeout(milliseconds, x)

Guards against indefinitely pending promises. Returns a Promise instance.

If x is neither a Promise instance or a thenable, the returned promise is fulfilled immediately.

If x is a thenable it is first assimilated into a promise.

If the promise fulfills or rejects before milliseconds have passed, the returned promise is fulfilled or rejected with the same value or reason, respectively. Otherwise the returned promise is rejected with a TimeoutError instance.

function timeout(milliseconds, x) { return new promise.Promise(function(resolve, reject) { var abort = timer(milliseconds, function() { reject(new TimeoutError('Timed out after ' + milliseconds + 'ms')); }); promise.Promise.from(x) .tap(resolve, reject) .ensure(abort); return abort; }); } exports.timeout = timeout;