英文:
Javascript "this" not set in function that was passed around
问题
以下是您要翻译的内容：
我有一个类，在其中有一个方法，该方法创建一个要由某些第三方库调用的函数。在函数内部，我想调用类成员，但在函数被调用的时候，“this”关键字不再设置。如何在函数内部使“this”关键字起作用？
我有一个过于简化的示例：
class myclass
{
printIt(x) {
console.log(x);
}
getFunc() {
return function(x) { this.printIt(x); };
}
}
(new myclass).getFunc()("test");
TypeError: Cannot read properties of undefined (reading 'printIt')
我也有一个解决方案，但我对此不太满意，并且我希望可以以更优雅的方式完成：
class myclass
{
printIt(x) {
console.log(x);
}
getFunc() {
let self = this;
return function(x) { self.printIt(x); };
}
}
(new myclass).getFunc()("test");
英文:
I have a class, in where I have a method that creates a function to be called by some third party library. Inside the function I want to call class members, but the "this" keyword is not set anymore at the moment the function is called. How can I get the this keyword to work inside the function?
I have an oversimplified example:
class myclass
{
printIt(x) {
console.log(x);
}
getFunc() {
return function(x) { this.printIt(x); };
}
}
(new myclass).getFunc()("test");
> TypeError: Cannot read properties of undefined (reading 'printIt')
And I also have a solution which I am not happy with, and which I expect can be done in a more elegant way:
class myclass
{
printIt(x) {
console.log(x);
}
getFunc() {
let self = this;
return function(x) { self.printIt(x); };
}
}
(new myclass).getFunc()("test");
答案1
得分: 2
class myclass {
printIt(x) {
console.log(x);
}
getFunc() {
return function(x) {
this.printIt(x);
}.bind(this);
}
}
(new myclass).getFunc()("test");
英文:
<!-- begin snippet: js hide: false console: true babel: false -->
<!-- language: lang-js -->
class myclass {
printIt(x) {
console.log(x);
}
getFunc() {
return function(x) {
this.printIt(x);
}.bind(this);
}
}
(new myclass).getFunc()("test");
<!-- end snippet -->
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