如何在jQuery 1.8.x中链接一系列延迟函数？

Question

鉴于这些功能:

function func1() {
  var dfd = $.Deferred();

  setTimeout(function() {
    dfd.resolve('Password');
  }, 1000);

  return dfd.promise();
}

function func2(message) {
  var dfd = $.Deferred();

  setTimeout(function() {
    if (message == 'Password') {
      dfd.resolve('Hello World');
    }
   }, 1000);

  return dfd.promise();
}

我想找到一个更好的方法来做到以下几点.注意这是使用jQuery 1.8.x.

var promise = func1();

promise.done(function(message1) {

  var promise2 = func2(message1);

  promise2.done(function(message2) {
    alert(message2);
  });
});

有任何想法吗？我认为使用jQuery #pipe或#then会起作用,但我无法弄明白.这是一个小提琴:http://jsfiddle.net/Z7prn/

Answer 1

它并不复杂(使用.then或者.pipe,我认为它们与jQuery 1.8相同).

func1().then(func2).done(function(message) {
    alert(message);
});

由于func2返回一个新的延迟对象,因此.done回调附加到该对象.

DEMO

Answer 2

我有一个类似的用例,所以我认为这应该可以帮到你.

以下方法将采用一组方法(可能会或可能不会返回Promises)并按顺序执行它们,等待每个延迟完成后再继续.默认行为是在失败时停止; 第二个参数允许您继续调用是否失败.

完成/失败处理程序签名是(Array < context >)函数(Array <Object {rejected | resolved:arguments }>),其中context是每个resolveWith/rejectWith调用的上下文,或者是延迟的问题,而arguments是参数在决议/拒绝中传递的集合.

(function ($) {
    "use strict";
    var copy = function (a) {
        return Array.prototype.slice.call(a);
    };

    /**
        Handle a sequence of methods, stopping on failure by default
        @param Array<Function> chain    List of methods to execute.  Non-deferred return values will be treated as successful deferreds.
        @param Boolean  continueOnFailure   Continue executing even if one of the returned deferreds fails.
        @returns Deferred
     */
    $.sequence = function (chain, continueOnFailure) {
        var handleStep, handleResult,
            steps = copy(chain),
            def = new $.Deferred(),
            defs = [],
            results = [];
        handleStep = function () {
            if (!steps.length) {
                def.resolveWith(defs, [ results ]);
                return;
            }
            var step = steps.shift(),
                result = step();
            handleResult(
                $.when(result).always(function () {
                    defs.push(this);
                }).done(function () {
                    results.push({ resolved: copy(arguments) });
                }).fail(function () {
                    results.push({ rejected: copy(arguments) });
                })
            );
        };
        handleResult = continueOnFailure ?
                function (result) {
                    result.always(function () {
                        handleStep();
                    });
                } :
                function (result) {
                    result.done(handleStep)
                        .fail(function () {
                            def.rejectWith(defs, [ results ]);
                        });
                };
        handleStep();
        return def.promise();
    };
}(this.jQuery));

一个简单的使用示例:http://jsfiddle.net/rG9rA/

function func1() {
  var dfd = $.Deferred();

  setTimeout(function() {
    dfd.resolve('Password');
  }, 1000);

  return dfd.promise();
}

function func2(message) {
  var dfd = $.Deferred();

  setTimeout(function() {
    if (message == 'Password') {
      dfd.resolve('Hello World');
    }
   }, 1000);

  return dfd.promise();
}

    $.sequence([func1, func2, function () { alert('done'); }]);