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我正在尝试创建一个静态函数，它将键名作为字符串接收并返回一个 lambda，它检查该字段是否包含另一个字符串。到目前为止，我所拥有的是这个（有些混乱的）代码：

type Only<T, K> = {
    [P in keyof T as (T[P] extends K ? P : never)]: T[P]
};

export class Functions {
    public static stringIncludesMatcherForKey<T>(key: keyof Only<T, string>): (a: T, b: string) => boolean {
        const stringifier = (obj: T) => (obj[key as unknown as keyof T] as unknown as string).toLowerCase() || '';
        return (obj: T, text: string) => stringifier(obj).includes(text);
    }
}

此函数将只接受具有字符串类型的键名。例如，如果您将其与以下界面一起使用：

interface Person {
    firstName: string;
    lastName: string;
    birthDate: Date;
}

class CheckPeople 
{
    Foo() {
        const firstNameMatcher = Functions.stringIncludesMatcherForKey<Person>('firstName'); // Fine
        const birthDateMatcher = Functions.stringIncludesMatcherForKey<Person>('birthDate'); // Error
    }
}

简而言之，该函数将只接受“firstName”或“lastName”作为键，而其他任何东西都按预期在我的 IDE 中显示错误。

但是，当我运行 ng build 时，它会输出一堆令人困惑的语法错误：

ERROR in src/app/_common/pipeline/Functions.ts:30:19 - error TS1005: ']' expected.

30     [P in keyof T as (T[P] extends K ? P : never)]: T[P]
                     ~~
src/app/_common/pipeline/Functions.ts:30:28 - error TS1005: ',' expected.

30     [P in keyof T as (T[P] extends K ? P : never)]: T[P]
                              ~~~~~~~
src/app/_common/pipeline/Functions.ts:30:50 - error TS1005: ';' expected.

30     [P in keyof T as (T[P] extends K ? P : never)]: T[P]
                                                    ~
src/app/_common/pipeline/Functions.ts:30:51 - error TS1128: Declaration or statement expected.

30     [P in keyof T as (T[P] extends K ? P : never)]: T[P]
                                                     ~
src/app/_common/pipeline/Functions.ts:31:1 - error TS1128: Declaration or statement expected.

31 };

我创建了以下StackBlitz，它表明该示例可以正常编译并按预期运行。

这意味着错误来自构建配置的差异，但我不知道在那里寻找什么。

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