使打字稿接口扩展另一个接口，不包括已经定义的键
对于我的 iPhone 上的一些 hacky 脚本（不是我为生产编写的代码），我经常发现自己将 string 视为 string[] （字符数组）。由于在手机上打字比在键盘上打字慢得多，并且考虑到 57 个字符宽的屏幕尺寸，字符非常宝贵，因此我编写了一些代码，采用 Array.prototype 的每个方法，将其映射到 Array.from(this)[fn]，并将其附加到 String.prototype 如果它尚不存在。例如，我希望 .slice() 仍然返回 string，而不是 string[]。
Object.entries(
Object.getOwnPropertyDescriptors(Array.prototype)
)
.filter(([n, d]) =>
!(n in String.prototype) &&
typeof d.value === 'function'
)
.forEach(([n]) =>
String.prototype[n] = function (...args) {
return Array.from(this)[n](...args)
}
)
现在我可以运行 'abc'.filter(x => x !== 'b') 并接收 ['a', 'c']。万岁。
现在，我想编写更新的接口字符串，而无需手动复制Array中的每个有效声明。 （有时 play.js 将读取 .d.ts 文件。）
我的最佳尝试引入了循环类型引用，这并不令我感到惊讶。
type MethodNames<T> = {
[K in keyof T & string]: T[K] extends (...args: any[]) => any ? K : never;
}[keyof T & string];
type MethodsOf<T> = {
[K in MethodNames<T>]: T[K];
};
type CharArray = Omit<MethodsOf<Array<string>>, keyof string>;
declare global {
interface String extends CharArray {}
}
export {};
<一href="https://www.typescriptlang.org/play?#code/C4TwDgpgBAshwAsD2ATAcgQwLYQM4B4AVAPigF4oBvAKCi gG0BpKASwDsoBrCEJAMyiEoAMii5gAJ3YBzALoAuQU1lQIAD2AQ2KXFAAUAOiMYJ03IoxsQ9WQEpypSyCgB+KM0VsIANwg SA3NQAvvTcvAJCouJSbHKB1KCQsPDIOgDyfESkFDR0TKwccIiomDgEJApKjLKBQfGJ0ADCCCYAghISGM4UaVgswPhFqbgZ +O2dIPjRMsTEADRcPPxikjPxKBAAxgA2JtDS20gARhjbVLQFmhJ8GJvQAMqrsaoaWjpQzW0dXVRBwdTUdRgJASYC-fxAA" rel="nofollow noreferrer">TS Playground
直到我使 String 扩展 CharArray 为止，一切正常。 CharArray 有正确的方法。添加扩展后，CharArray 会尝试排除其自己的成员，因为这些成员现在是 String 的成员。
我所问的可能吗？我怀疑答案是否，但我想我会问。
For some hacky scripting on my iPhone (not code I would ever write for production), I frequently find myself treating strings as string[] (a character array). Since typing on a phone is significantly slower than on a keyboard and characters are at a premium given the 57-character-wide screen size, I wrote some code that takes every method of Array.prototype, maps it to Array.from(this)[fn], and attaches it to String.prototype if it does not already exist. For example, I want .slice() still to return a string, not a string[].
Object.entries(
Object.getOwnPropertyDescriptors(Array.prototype)
)
.filter(([n, d]) =>
!(n in String.prototype) &&
typeof d.value === 'function'
)
.forEach(([n]) =>
String.prototype[n] = function (...args) {
return Array.from(this)[n](...args)
}
)
Now I can run 'abc'.filter(x => x !== 'b') and receive ['a', 'c']. Huzzah.
Now I want to write the updated interface String without manually copying over every valid declaration from Array<T>. (Sometimes play.js will read a .d.ts file.)
My best attempt introduces circular type references, which doesn't surprise me.
type MethodNames<T> = {
[K in keyof T & string]: T[K] extends (...args: any[]) => any ? K : never;
}[keyof T & string];
type MethodsOf<T> = {
[K in MethodNames<T>]: T[K];
};
type CharArray = Omit<MethodsOf<Array<string>>, keyof string>;
declare global {
interface String extends CharArray {}
}
export {};
Up until I make String extend CharArray, everything works fine. CharArray has the proper methods. Once I add the extension, CharArray tries to exclude its own members, since those members are now members of String.
Is what I'm asking even possible? I suspect the answer is no, but I thought I would ask.
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就在发布这个问题之前几秒钟，我突然想到了一个想法，而且它确实有效。不要排除
keyof string（这是Omit所做的），而是让CharArray使用string[K]如果存在。现在，虽然引擎可以争论循环引用，但它只是将
string的属性与其自身合并，所以它并不关心。 （至少，我认为这就是原因。）Mere seconds before posting this question, an idea occurred to me, and it works. Rather than excluding
keyof string(which is whatOmitdoes), makeCharArrayusestring[K]if it exists.Now, while the engine could argue a circular reference, it's only merging the properties of
stringwith themselves, so it doesn't care. (At least, I think that's the reason.)