动态方法名称
在命名方法时,还可以评估表达式,类似于使用 []
访问对象属性的方法。这对于拥有动态属性名称很有用,但通常与符号一起使用。
let METADATA = Symbol('metadata');
class Car {
constructor(make, model) {
this.make = make;
this.model = model;
}
// example using symbols
[METADATA]() {
return {
make: this.make,
model: this.model
};
}
// you can also use any javascript expression
// this one is just a string, and could also be defined with simply add()
["add"](a, b) {
return a + b;
}
// this one is dynamically evaluated
[1 + 2]() {
return "three";
}
}
let MazdaMPV = new Car("Mazda", "MPV");
MazdaMPV.add(4, 5); // 9
MazdaMPV[3](); // "three"
MazdaMPV[METADATA](); // { make: "Mazda", model: "MPV" }