debouncing in a class

debounceable.js

class Base {
    constructor () {
    super()

    /**
     * @type {null | Map<object | string | number | symbol, ReturnType<typeof setTimeout>>}
     */
    this.__debounceMap__ = null
  }

  /**
   * @param {(...args: any[]) => any} callback
   * @param {{ key: any, wait?: number }} options
   * @return {ReturnType<typeof setTimeout>}
   */
  debounce (callback, options) {
    if (this.__debounceMap__ == null) {
      this.__debounceMap__ = new Map()
    }
    
    if (options.wait == null) options.wait = 0

    let timeout = this.__debounceMap__.get(options.key)

    if (timeout) {
      clearTimeout(timeout)
    }

    timeout = setTimeout(() => {
      callback()
    }, options.wait)

    this.__debounceMap__.set(options.key, timeout)

    return timeout
  }

}

// Usage

class MyClass extends Base {
  doExpensiveThing () {
    this.debounce(() => {
        this.calculateAllTheThing()
    }, { wait: 300, key: this.doExpensiveThing })
  }
}