如何将回调样本转换为延迟对象?

本文介绍了如何将回调样本转换为延迟对象?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个接受回调函数的函数，该函数将数据传回.可以将其转换为递延对象以进行更好的练习吗?

I have a function that accepts a callback function where I pass the data back in. Can this converted to a deferred object for better practice?

这就是我得到的:

var chapters; var getChapters = function (fnLoad) { //CACHE DATA IF APPLICABLE if (!chapters) { //CALL JSON DATA VIA AJAX $.getJSON('/chapters.txt') .done(function (json) { //STORE DATA IN LOCAL STORAGE chapters = Lawnchair(function () { this.save(json, function (data) { //CALL CALLBACK ON DATA fnLoad(data); }); }); }); } else { //RETURN ALREADY CREATED LOCAL STORAGE chapters.all(function (data) { //CALL CALLBACK ON DATA fnLoad(data); }); } };

然后我像这样简单地使用它:

Then I simply use it like this:

this.getChapters(function (data) { console.log(data); });

在保持高速缓存方法的同时，如何像承诺一样使用它?

How can I use it like a promise though while maintaining the cache approach?

this.getChapters().done(function (data) { console.log(data); });

推荐答案

var chapters; var getChapters = function (fnLoad) { var d = new $.Deferred(); //CACHE DATA IF APPLICABLE if (!chapters) { //CALL JSON DATA VIA AJAX $.getJSON('/chapters.txt') .done(function (json) { //STORE DATA IN LOCAL STORAGE chapters = Lawnchair(function () { this.save(json, function (data) { //CALL CALLBACK ON DATA d.resolve(data); }); }); }) .fail(function() { d.reject(); }); } else { //RETURN ALREADY CREATED LOCAL STORAGE chapters.all(function (data) { //CALL CALLBACK ON DATA d.resolve(data); }); } return d.promise(); };

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