javascript – 如何使jQuery Deferred对象以另一个延迟的“已解决/已拒绝”状态解析/拒绝？

2019年8月4日 130次阅读

我正在编写几个有效延迟对象的函数,这些函数依赖于其他延迟对象的不同组合.

function takesOneSecond() {
    return $.Deferred(function(deferred) {
        // Does something...
    }).promise();
}

function takesOneMinute() {
    return $.Deferred(function(deferred) {
        // Does something...
    }).promise();
}

function takesThreeMinutes() {
    return $.Deferred(function(deferred) {
        // Does something...
    }).promise();
}

function mySwitchingFunction() {

    return $.Deferred(function(deferred) {

        // Does something here..
        // Effectively chooses one of several other functions to call.

        if(/* choose 1 second */) {

            // We tie ourselves to the '1 second' function.

            // Call that function.
            takesOneSecond().done(function() {

                deferred.resolve(); // If that's done, I'm done too.

            }).fail(function() {

                deferred.reject(); // If that failed, I've failed too.

            });

        } else if(/* choose 1 minute */) {

            // Etc..

        } else if(/* choose 3 minutes */) {

            // Etc..

        }

    }).promise();

}

我正在写这段代码很多,没有其他方法可以制作延迟镜像或级联相同的“已解决”或“被拒绝”的另一种延迟状态吗？

takesOneSecond().done(function() {
    deferred.resolve(); // If that's done, I'm done too.
}).fail(function() {
    deferred.reject(); // If that failed, I've failed too.
});

最佳答案 我认为你根本不需要构建新的承诺.回到第一个承诺.

function mySecondFunction() {
    // Does something here..
    // Effectively chooses one of several other functions to call.
    // In this case, assume I've just chosen the 'myFirstFunction' function.

    // Call that function and return its promise
    return myFirstFunction();
}

如果你想强调“同时”部分但可能用不同的值解决,你可以通过链接.then创建一个新的：

function mySecondFunction() {
    return myFirstFunction().then(function(resultOfFirst) {
        // but ignore it and
        return differentResult;
    }); // errors will propagate automatically
}
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