typescript 如何从打字稿中的实例方法访问静态成员？
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How to access static members from instance methods in typescript?
提问by Simon Hürlimann
I try to use a static member from an instance method. I know about accessing static member from non-static function in typescript, but I do not want to hard code the class to allow inheritance:
我尝试使用实例方法中的静态成员。我知道从 typescript 中的非静态函数访问静态成员，但我不想对该类进行硬编码以允许继承：
class Logger {
protected static PREFIX = '[info]';
public log(msg: string) {
console.log(Logger.PREFIX + ' ' + msg); // What to use instead of Logger` to get the expected result?
}
}
class Warner extends Logger {
protected static PREFIX = '[warn]';
}
(new Logger).log('=> should be prefixed [info]');
(new Warner).log('=> should be prefixed [warn]');
I've tried things like
我试过这样的事情
typeof this.PREFIX
回答by basarat
You simply need ClassName.property:
你只需要ClassName.property：
class Logger {
protected static PREFIX = '[info]';
public log(message: string): void {
alert(Logger.PREFIX + string);
}
}
class Warner extends Logger {
protected static PREFIX = '[warn]';
}
MORE
更多的
from : http://basarat.gitbooks.io/typescript/content/docs/classes.html
来自：http: //basarat.gitbooks.io/typescript/content/docs/classes.html
TypeScript classes support static properties that are shared by all instances of the class. A natural place to put (and access) them is on the class itself and that is what TypeScript does:
TypeScript 类支持由类的所有实例共享的静态属性。放置（和访问）它们的自然位置是在类本身上，这就是 TypeScript 所做的：
class Something {
static instances = 0;
constructor() {
Something.instances++;
}
}
var s1 = new Something();
var s2 = new Something();
console.log(Someting.instances); // 2
UPDATE
更新
If you want it to inherit from the particular instance's constructor use this.constructor. Sadly you need to use sometype assertion. I am using typeof Loggershown below:
如果您希望它从特定实例的构造函数继承，请使用this.constructor. 遗憾的是，您需要使用某种类型断言。我正在使用typeof Logger如下所示：
class Logger {
protected static PREFIX = '[info]';
public log(message: string): void {
var logger = <typeof Logger>this.constructor;
alert(logger.PREFIX + message);
}
}
class Warner extends Logger {
protected static PREFIX = '[warn]';
}
