code example is not correct in Intersection Types section

Code

function extend<First, Second>(first: First, second: Second): First & Second {
    const result: Partial<First & Second> = {};
    for (const prop in first) {
        if (first.hasOwnProperty(prop)) {
            (result as First)[prop] = first[prop];
        }
    }
    for (const prop in second) {
        if (second.hasOwnProperty(prop)) {
            (result as Second)[prop] = second[prop];
        }
    }
    return result as First & Second;
}

class Person {
    constructor(public name: string) { }
}

interface Loggable {
    log(name: string): void;
}

class ConsoleLogger implements Loggable {
    log(name) {
        console.log(`Hello, I'm ${name}.`);
    }
}

const jim = extend(new Person('Jim'), ConsoleLogger.prototype);
jim.log(jim.name);

class methods are non-enumerable, so the second for...in loop will not add log method to the result obj.

找到 Intersection Types 文档部分并检查其中展示的 extend 示例，然后验证类方法在生成的 JavaScript 中的行为。当示例及其文档说明的行为不再与类方法的不可枚举性冲突时，即视为完成。