JavaScript promise 返回

Question

这个问题已经有答案了:

How do I return the response from an asynchronous call? (42 个回答)

已关闭 8 年前。

我正在尝试创建一个使用 Promise 返回 api 调用主体的函数。我的代码是

function checkApi(link) {
    var promise = new Promise(function(resolve, reject) {
        //query api
    });
    promise.then(function(value) {
        console.log(value); //want to return this, this would be the body
    }, function(reason) {
        console.log(reason); //this is an error code from the request
    });
}

var response = checkApi('http://google.com');
console.log(response);

我不想执行控制台日志，而是想返回 google.com 的正文，以便我可以使用它。这只是一个范围问题，但我不知道如何解决它。谢谢，

Answer 1

您可以返回 Promise，然后当您调用 checkApi 时，您可以附加另一个 .then()。

function checkApi(link) {
    var promise = new Promise(function(resolve, reject) {
        //query api
    });
    return promise.then(function(value) {
        console.log(value); //Here you can preprocess the value if you want,
                            //Otherwise just remove this .then() and just 
        return value;       //use a catch()
    }, function(reason) {
        console.log(reason); //this is an error code from the request
    });
}

//presuming this is not the global scope.
var self = this;
checkApi('http://google.com')
    .then(function (value){
         // Anything you want to do with this value in this scope you have
         // to do it from within this function.
         self.someFunction(value);
         console.log(value)
    });