在此用例中，$ interval和$ timeout之间是否有真正的区别? [英] Is there a real difference between $interval and $timeout in this use case?

问题描述

两者之间是否存在真正的区别

Is there a real difference between:

$interval(function () {
  doSomething();
}, 250, 1, true);

和

$timeout(function () {
  doSomething();
}, 250);

• 两个回报承诺
• 两个都执行一次 doSomething()一次.
• 两者都触发摘要循环.

我可能注意到的唯一可能的区别是，如果对 $ interval 的最后一个参数使用 false ，则可以绕过摘要循环.

The only possible difference I could notice is that I could bypass a digest cycle if I use false for the last parameter of $interval.

推荐答案

让我们做一些代码分析

function timeout(fn, delay, invokeApply) {
  var deferred = $q.defer(),
      promise = deferred.promise,
      skipApply = (isDefined(invokeApply) && !invokeApply),
      timeoutId;

  timeoutId = $browser.defer(function() {
    try {
      deferred.resolve(fn());
    } catch(e) {
      deferred.reject(e);
      $exceptionHandler(e);
    }
    finally {
      delete deferreds[promise.$$timeoutId];
    }

    if (!skipApply) $rootScope.$apply();
  }, delay);

  promise.$$timeoutId = timeoutId;
  deferreds[timeoutId] = deferred;

  return promise;
}

间隔

function interval(fn, delay, count, invokeApply) {
  var setInterval = $window.setInterval,
      clearInterval = $window.clearInterval,
      deferred = $q.defer(),
      promise = deferred.promise,
      iteration = 0,
      skipApply = (isDefined(invokeApply) && !invokeApply);

  count = isDefined(count) ? count : 0;

  promise.then(null, null, fn);

  promise.$$intervalId = setInterval(function tick() {
    deferred.notify(iteration++);

    if (count > 0 && iteration >= count) {
      deferred.resolve(iteration);
      clearInterval(promise.$$intervalId);
      delete intervals[promise.$$intervalId];
    }

    if (!skipApply) $rootScope.$apply();

  }, delay);

  intervals[promise.$$intervalId] = deferred;

  return promise;
}

最后的区别是不正确的，因为这两种方法都实现了 if(！skipApply)$ rootScope.$ apply(); 没有没有区别.

Last difference is not true as both of methods implements if (!skipApply) $rootScope.$apply(); There is no difference.

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