jQuery 中的 .always() 或 .then() 回调先发生什么？

Question

如果您有一个同时具有 .then 和 .always 回调的函数，哪个会先执行？

Answer 1

摘自 deferred.resolve() 文档：

When the Deferred is resolved, any doneCallbacks added by deferred.then() or deferred.done() are called. Callbacks are executed in the order they were added.

示例如下：

var $logger = $("#logEntry");
function addLog(content){
   $logger.append($("<li/>").html(content));
}

var newPromise = $.Deferred();

$.when(newPromise).done(function() {
    addLog("1st $when().done!");
});

newPromise.then(function() {
    addLog("1st then!");
}).always(function() {
    addLog("1st always!");
}).done(function() {
    addLog("1st done!");
}).done(function() {
    addLog("2nd done!");
}).always(function() {
    addLog("2nd always!");
}).then(function() {
    addLog("2nd then!");
});

$.when(newPromise).done(function() {
    addLog("2nd $when().done!");
});

addLog("Resolving promise!");

newPromise.resolve();

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<ul id="logEntry"></ul>

jQuery 中的 .always() 或 .then() 回调先发生什么？

What comes first .always() or .then() callbacks in jQuery?

javascript

jquery

deferred-execution

deferred