nfywt-wx/wx.demo.ywtinfo.com/js/asset/deferred.js

//     Zepto.js
//     (c) 2010-2016 Thomas Fuchs
//     Zepto.js may be freely distributed under the MIT license.
//
//     Some code (c) 2005, 2013 jQuery Foundation, Inc. and other contributors

;(function($){
    var slice = Array.prototype.slice

    function Deferred(func) {
        var tuples = [
                // action, add listener, listener list, final state
                [ "resolve", "done", $.Callbacks({once:1, memory:1}), "resolved" ],
                [ "reject", "fail", $.Callbacks({once:1, memory:1}), "rejected" ],
                [ "notify", "progress", $.Callbacks({memory:1}) ]
            ],
            state = "pending",
            promise = {
                state: function() {
                    return state
                },
                always: function() {
                    deferred.done(arguments).fail(arguments)
                    return this
                },
                then: function(/* fnDone [, fnFailed [, fnProgress]] */) {
                    var fns = arguments
                    return Deferred(function(defer){
                        $.each(tuples, function(i, tuple){
                            var fn = $.isFunction(fns[i]) && fns[i]
                            deferred[tuple[1]](function(){
                                var returned = fn && fn.apply(this, arguments)
                                if (returned && $.isFunction(returned.promise)) {
                                    returned.promise()
                                        .done(defer.resolve)
                                        .fail(defer.reject)
                                        .progress(defer.notify)
                                } else {
                                    var context = this === promise ? defer.promise() : this,
                                        values = fn ? [returned] : arguments
                                    defer[tuple[0] + "With"](context, values)
                                }
                            })
                        })
                        fns = null
                    }).promise()
                },

                promise: function(obj) {
                    return obj != null ? $.extend( obj, promise ) : promise
                }
            },
            deferred = {}

        $.each(tuples, function(i, tuple){
            var list = tuple[2],
                stateString = tuple[3]

            promise[tuple[1]] = list.add

            if (stateString) {
                list.add(function(){
                    state = stateString
                }, tuples[i^1][2].disable, tuples[2][2].lock)
            }

            deferred[tuple[0]] = function(){
                deferred[tuple[0] + "With"](this === deferred ? promise : this, arguments)
                return this
            }
            deferred[tuple[0] + "With"] = list.fireWith
        })

        promise.promise(deferred)
        if (func) func.call(deferred, deferred)
        return deferred
    }

    $.when = function(sub) {
        var resolveValues = slice.call(arguments),
            len = resolveValues.length,
            i = 0,
            remain = len !== 1 || (sub && $.isFunction(sub.promise)) ? len : 0,
            deferred = remain === 1 ? sub : Deferred(),
            progressValues, progressContexts, resolveContexts,
            updateFn = function(i, ctx, val){
                return function(value){
                    ctx[i] = this
                    val[i] = arguments.length > 1 ? slice.call(arguments) : value
                    if (val === progressValues) {
                        deferred.notifyWith(ctx, val)
                    } else if (!(--remain)) {
                        deferred.resolveWith(ctx, val)
                    }
                }
            }

        if (len > 1) {
            progressValues = new Array(len)
            progressContexts = new Array(len)
            resolveContexts = new Array(len)
            for ( ; i < len; ++i ) {
                if (resolveValues[i] && $.isFunction(resolveValues[i].promise)) {
                    resolveValues[i].promise()
                        .done(updateFn(i, resolveContexts, resolveValues))
                        .fail(deferred.reject)
                        .progress(updateFn(i, progressContexts, progressValues))
                } else {
                    --remain
                }
            }
        }
        if (!remain) deferred.resolveWith(resolveContexts, resolveValues)
        return deferred.promise()
    }

    $.Deferred = Deferred
})(Zepto)