javascript - 您如何从函数访问该对象的函数的对象（this.someProperty）的属性？

Question

我已经看到了很多关于如何访问对象属性的答案，但没有看到如何从该对象的函数中访问它们。所以我的问题是：

• 您如何从函数访问该对象的函数的对象的属性？

例如，查看下面的代码...

// Wanted output:
1. Original settings // (a String)
2. Original settings // (a String)

这是代码：

 class Animal {

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

    changeSettings(newSettings) {
        console.log("1. ", this.settings); // Prints OK. 

        checkOldSettings();

        function checkOldSettings() {
            console.log("2. ", this.settings); // This causes an error, as 'this' is undefined.
        }
    }
}

//==============================================================================

class Dog extends Animal {

}

//==============================================================================

let dog = new Dog("Origingal settings");   
dog.changeSettings("... Whatever settings, not important here...");

干杯

标签： javascriptobjectthis