[英]Unable to access/get value of abstract (base) class properties from derived class - TypeScript
[英]Access properties from derived class
abstract class Base {
constructor() {
console.log(this.components)
}
components = ['']
}
class Child extends Base {
components = ['button', 'text']
}
const f = new Child()
运行这段代码,我得到
['']
但我想得到
['button', 'text']
从派生的类。 我想这样做的原因:我想验证用户在Child中定义的“组件”属性。 不可能吗?
在调用基类中的构造函数之后,立即设置components属性:
abstract class Base {
constructor() {
console.log(this.components)
}
components = ['']
}
class Child extends Base {
constructor() {
// inherited components from base = ['']
super() // Call base constructor
// this.components = ['button', 'text']
}
components = ['button', 'text']
}
const f = new Child()
您需要等待基本构造函数同步完成,然后才能访问新值-即。 通过使用setTimeout
:
constructor() {
setTimeout(() => console.log(this.components))
}
理想情况下,您应该将组件作为参数传递:
abstract class Base {
constructor(public components = ['']) {
console.log(components)
}
}
class Child extends Base {
constructor() {
super(['button', 'text'])
// this.components = ['button', 'text']
}
}
const f = new Child()
尝试这个:
abstract class Base {
constructor(components) {
console.log(components)
}
}
class Child extends Base {
constructor() {
super(['button', 'text'])
}
}
const f = new Child()
要么
abstract class Base {
constructor(components) {
console.log(components)
}
}
class Child extends Base {
}
const f = new Child(['button', 'text'])
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