如何在promise.then()中检索对此的引用? [英] how can I retrieve a reference to this in a promise.then ()?

问题描述

javascript/Node.js

javascript / Node.js

我如何在promise中检索对此对象的引用.然后?

how can I retrieve a reference to this/object inside a promise.then ?

var controller = new MyController(params);

controller.action_send();

/////////////////////////////////

class MyController{

    constructor(params)
    {
        this.params = params;
    }

    action_send()
    {
        var promise = ext_lib.send();


        promise.then(
            function(details) {

                this.action_save(details);
                //(node:27014) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'action_save' of undefined
           });
   }

    action_save(details)
    {  
     save (this.params, details);
    }   
}

PHPStorm警告说警告不要尝试通过此方法引用ECMAScript类的成员的常见错误.不是lambda的嵌套函数中的限定符.嵌套函数(不是lambda)中的this是函数本身的"this"，与外部类无关.

a PHPStorm warning says Warns against a common mistake of trying to reference a member of an ECMAScript class via this. qualifier in a nested function that is not a lambda. this in a nested function that is not a lambda is the function's own 'this' and doesn't relate to the outer class.

从现在开始tks

推荐答案

使用箭头功能.

与常规函数不同，箭头函数不会绑定 this .取而代之的是，这是按词法绑定的(即，其含义与其原始上下文无关).

Unlike a regular function, an arrow function does not bind this. Instead, this is bound lexically (i.e. this keeps its meaning from its original context).

这里有更多有关它的详细信息箭头功能

Here are more details about it Arrow Functions

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