Javascript 从构造函数调用类方法
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Calling a class method from the constructor
提问by Vivek Kumar
I'm getting an error when calling a class method from its constructor. Is it possible to call a method from the constructor? I tried calling the base class method from the constructor of a derived class but I am still getting an error.
从其构造函数调用类方法时出现错误。是否可以从构造函数调用方法？我尝试从派生类的构造函数调用基类方法，但仍然出现错误。
'use strict';
class Base {
constructor() {
this.val = 10;
init();
}
init() {
console.log('this.val = ' + this.val);
}
};
class Derived extends Base {
constructor() {
super();
}
};
var d = new Derived();
? js_programs node class1.js /media/vi/DATA/programs/web/js/js_programs/class1.js:7 init(); ^
ReferenceError: init is not defined at Derived.Base (/media/vi/DATA/programs/web/js/js_programs/class1.js:7:9) at Derived (/media/vi/DATA/programs/web/js/js_programs/class1.js:18:14) at Object. (/media/vi/DATA/programs/web/js/js_programs/class1.js:23:9) at Module._compile (module.js:435:26) at Object.Module._extensions..js (module.js:442:10) at Module.load (module.js:356:32) at Function.Module._load (module.js:311:12) at Function.Module.runMain (module.js:467:10) at startup (node.js:136:18) at node.js:963:3 ? js_programs
? js_programs 节点 class1.js /media/vi/DATA/programs/web/js/js_programs/class1.js:7 init(); ^
ReferenceError: init is not defined at Derived.Base (/media/vi/DATA/programs/web/js/js_programs/class1.js:7:9) at Derived (/media/vi/DATA/programs/web/js/ js_programs/class1.js:18:14) 在对象。(/media/vi/DATA/programs/web/js/js_programs/class1.js:23:9) at Module._compile (module.js:435:26) at Object.Module._extensions..js (module.js :442:10) at Module.load (module.js:356:32) at Function.Module._load (module.js:311:12) at Function.Module.runMain (module.js:467:10) 启动时(node.js:136:18) 在 node.js:963:3 ？js_programs
回答by deceze
You're calling the functioninit(), not the methodinitof either Baseor the current object. No such function exists in the current scope or any parent scopes. You need to refer to your object:
你调用的函数init()，而不是方法init的任一Base或当前对象。当前作用域或任何父作用域中不存在此类函数。您需要引用您的对象：
this.init();
回答by madox2
You are missing thiskeyword:
您缺少this关键字：
this.init();
