deleteFromArray.tsx

const data = {
    numbers: [1, 2, 3],
    strings: ['a', 'b', 'c'],
    notNumbers: 'Hello, world.'
}

deleteFromArray(data, 'numbers', num => num === 2)

function deleteFromArray<O, K extends keyof O, T>(
    obj: O,
    key: O[K] extends Array<T> ? K : never,
    func: O[K] extends Array<T> ? (v: O[K][0]) => boolean : never
) {
    const arr = obj[key]

    // Why is this necessary if a value is only assignable
    // to `key` if `obj[key]` is an array?
    if (!Array.isArray(arr)) {
        throw new Error('Value is not an array')
    }

    return arr.filter(v => !func(v))
}