以下代码返回:
output.isPending?: true
output.isRejected?: false
output.isFulfilled?: false
为什么？我期望 output.isRejected 为 true。
<html>
<head>
<script src="http://cdnjs.cloudflare.com/ajax/libs/q.js/0.9.7/q.js"></script>
<script src="http://jasmine.github.io/2.3/lib/jasmine.js"></script>
</head>
<body>
</body>
<script>
var output, bar;
bar = {
doSomethingAsync: function() {
var d = Q.defer();
d.resolve('result');
return d.promise;
}
};
function Foo(bar) {
this._bar = bar;
this.go = function() {
var deferred = Q.defer();
this._bar.doSomethingAsync()
.then(onSuccess.bind(this, deferred));
return deferred.promise;
}
};
function onSuccess(deferred, result) {
deferred.reject();
}
output = new Foo(bar).go()
.finally(function() {
console.log('output.isPending?:', output.isPending());
console.log('output.isRejected?:', output.isRejected());
console.log('output.isFulfilled?:', output.isFulfilled());
});
</script>
</html>
最佳答案
因为 output 不是 new Foo(bar).go()。它被赋予 .finally() 调用的结果，并且在 finally 回调完成之前不会被解析。
这将按预期工作:
var output = new Foo(bar).go();
output.finally(function() {
console.log('output.isPending?:', output.isPending());
console.log('output.isRejected?:', output.isRejected());
console.log('output.isFulfilled?:', output.isFulfilled());
});
关于javascript - 为什么 promise 仍然悬而未决？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30329485/