`endsWith` typeguard

endsWith.ts

type EndsWithResult<S extends string, E extends string> = S extends `${string}${E}` ? S : `${S}${E}`

const endsWith = <E extends string>(end: E) => <S extends string>(str: S): str is EndsWithResult<S, E> => {
    return str.slice(-end.length) === end;
}
const str = 'something' as `some${string}`;
const qqq = endsWith('foo')(str);

if (qqq) {
    str;
} else {
    str;
}

const strWithFoo = 'somefoo';
const qq = endsWith('foo')(strWithFoo);

if (qq) {
    strWithFoo;
} else {
    strWithFoo;
}

const strArr = ['some', 'somefoo', 'something'] as (`some${string}`)[];

const q = strArr.filter(endsWith('foo'));