rendezvous with cassidoo #179 - Interview question of the week

hashmap.js

//Design a hashmap without using any built-in libraries. You should include the following functions:
// - put(key, value): Insert a (key, value) pair into the hashmap. If the value already exists, update the value.
// - get(key): Returns the value to which key is mapped, or -1 if this map contains nothing for key.
// - remove(key): Remove the mapping for the value in key if it exists.

class HashMap {
    #buffer = []

    put(key, value) {
        let index = 0
        while (index in this.#buffer && this.#buffer[index] !== key) index += 2
        this.#buffer[index] = key
        return this.#buffer[index + 1] = value
    }

    get(key) {
        for (let index = 0; this.#buffer[index]; index += 2)
            if (this.#buffer[index] === key) return this.#buffer[index + 1]
        return -1
    }

    remove(key) {
        let doRemove = false
        for (var index = 0; this.#buffer[index]; index += 2) {
            if (this.#buffer[index] === key) doRemove = true
            if (doRemove) {
                if ((index + 2) in this.#buffer) {
                    this.#buffer[index] = this.#buffer[index + 2]
                    this.#buffer[index + 1] = this.#buffer[index + 3]
                }
                else this.#buffer.length = index
            }
        }
    }
}