Question

我遵循了这些docs并设置了一个mixin类：

class ClassA {
    firstName(): string {
        return "James";
    }
}
class ClassB {
    lastName(): string {
        return "Bond";
    }
}

class Mixin {} // <--

interface Mixin extends ClassA, ClassB {}

function applyMixins(derivedCtor: any, baseCtors: any[]) {
    baseCtors.forEach(baseCtor => {
        Object.getOwnPropertyNames(baseCtor.prototype).forEach(name => {
            Object.defineProperty(derivedCtor.prototype, name, Object.getOwnPropertyDescriptor(baseCtor.prototype, name));
        });
    });
}

applyMixins(Mixin, [ClassA, ClassB])

for (const name of Object.getOwnPropertyNames(ClassA.prototype)) {
    const method = ClassA.prototype[name];
    if (typeof method === "function") {
        Mixin.prototype[name] = ClassA.prototype[name];
    }
}
for (const name of Object.getOwnPropertyNames(ClassB.prototype)) {
    const method = ClassB.prototype[name];
    if (typeof method === "function") {
        Mixin.prototype[name] = ClassB.prototype[name];
    }
}
const mixin = new Mixin();
console.log("Mixin contains: " + mixin.firstName() + " and " + mixin.lastName());
const asClassA = mixin as ClassA;
console.log(asClassA);
const asClassB = mixin as ClassB;
console.log(asClassB);

const isIstanceOfA = (mixin instanceof ClassA);
console.log(isIstanceOfA);
const isIstanceOfB = (mixin instanceof ClassB);
console.log(isIstanceOfB);

使用mixinclass时，无法正确将其强制转换为ClassA / ClassB。并且使用instanceOf-我得到了假。

mixin类丢失了原始类型吗？还是我错过了什么？

它打印：

Mixin包含：James和Bond

ClassB {}

ClassB {}

false

false

到控制台。

我找到了另一个typescript doc example。还有另一个示例here。 Here。但是用ts-node运行它们，我得到：

ReferenceError：__extends未定义

function Tagged<T extends Constructor<{}>>(Base: T) {
    return class extends Base { // <-- error thrown here
        _tag: string;
        constructor(...args: any[]) {
            super(...args);
            this._tag = "";
        }
    }
}

虽然可以运行它NativeScript，但是我最初打算使用它。

类型混入后丢失了吗？

0 个答案: