javascript 中 Promise 的语法令人困惑 [英] Syntax of Promises in javascript is confusing

问题描述

要访问对象的方法，我们使用点运算符，如 nameOfObject.nameOfMethod().这就是我对点运算符的理解.

To access a method of the object we use dot operator like nameOfObject.nameOfMethod(). This is how I understand the dot operator.

对点运算符的这种理解并不能帮助我理解 JavaScript 中 promise 的语法.例如看下面的代码:

This understanding of the dot operator is not helping me understand the syntax of promises in JavaScript. E.g see the code below:

var askMom = function () {
    willIGetNewPhone // calling the promise
        .then(function (fulfilled1) {
            // yay, you got a new phone
            console.log(fulfilled);
        })
        .then(function (fulfilled2) {
            // yay, you got a new phone
            console.log(fulfilled2);
        })
        .catch(function (error) {
            // ops, mom don't buy it
            console.log(error.message);
        });
}

在我看来好像代码在说 - nameOfObject.thenMehtod().thenMethod().catchMethod();

It appears to me as if the code is saying - nameOfObject.thenMehtod().thenMethod().catchMethod();

我怎么理解这个?这是否意味着在 JavaSript 中使用 nameOfObject.method1().method2().method3;

How do I understand this? Does it mean it's normal in JavaSript to call methods of an object by using nameOfObject.method1().method2().method3;

推荐答案

当您调用 .then() 时，您就像在执行任何其他函数一样.然后它返回一个承诺，它也可以调用 .then() 或 .catch() .

When you call .then(), you're executing a function just like any other. It then returns a promise that also can have .then() or .catch() called on it.

这通常称为链接".

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