key-container.ts

/*
  Copyright 2017 Alex Jover Morales (alexjovermorales@gmail.com)

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
 */

export interface IStateKey {
  name: string,
  code: number
}

/**
 * Contains the logic for the keyMapping
 *
 * @class KeyContainer
 */
export class KeyContainer {
  /**
   * Map of allowed keys
   */
  private keyMap: {[a: string]: number|number[]} = {
    // nums
    '0': 48,
    '1': 49,
    '2': 50,
    '3': 51,
    '4': 52,
    '5': 53,
    '6': 54,
    '7': 55,
    '8': 56,
    '9': 57,

    // characters
    'a': 65,
    'b': 66,
    'c': 67,
    'd': 68,
    'e': 69,
    'f': 70,
    'g': 71,
    'h': 72,
    'i': 73,
    'j': 74,
    'k': 75,
    'l': 76,
    'm': 77,
    'n': 78,
    'o': 79,
    'p': 80,
    'q': 81,
    'r': 82,
    's': 83,
    't': 84,
    'u': 85,
    'v': 86,
    'w': 87,
    'x': 88,
    'y': 89,
    'z': 90,

    // punctuation
    ',': 188,
    '.': 190,

    // special
    'shift': 16,
    'ctrl': 17,
    'alt': 18,
    'esc': 27,
    'escape': 27,

    // navigation
    'left': 37,
    'right': 39,
    'up': 38,
    'down': 40,
    'backspace': 8,
    'enter': 13,
    'pageup': 33,
    'pagedown': 34,
    'end': 35,
    'home': 36,
    'tab': 9,

    // numpad
    'num0': 96,
    'num1': 97,
    'num2': 98,
    'num3': 99,
    'num4': 100,
    'num5': 101,
    'num6': 102,
    'num7': 103,
    'num8': 104,
    'num9': 105,
    'num*': 106,
    'num+': 107,
    'num-': 109,
    'num.': 110,
    'num/': 111,

    // function keys
    'f1': 112,
    'f2': 113,
    'f3': 114,
    'f4': 115,
    'f5': 116,
    'f6': 117,
    'f7': 118,
    'f8': 119,
    'f9': 120,
    'f10': 121,
    'f11': 122,
    'f12': 123
  }

  private stateKeys: IStateKey[] = [
    { name: 'shift', code: 16 },
    { name: 'ctrl', code: 17 },
    { name: 'alt', code: 18 }
  ]

  /**
   * Reversed map (value: key) for easy mapping code -> word
   */
  private keyMapReversed: { [keyCode: number]: string }

  /**
   * Initializes the keyMaps
   *
   * @param {any} platform
   * @param {any} userAgent
   */
  public init(platform, userAgent) {
    this.stateKeys = [
      { name: 'shift', code: 16 },
      { name: 'ctrl', code: 17 },
      { name: 'alt', code: 18 }
    ]

    // Define cmdKey depending on browser
    let cmdKey: number|number[] = [91, 93]

    if (platform.match('Mac') && userAgent.match('Opera')) {
      cmdKey = [17]
    } else if (platform.match('Mac') && userAgent.match('Firefox')) {
      cmdKey = [224]
    }

    this.keyMap = Object.assign(this.keyMap, { 'cmd': cmdKey })
    this.keyMapReversed = this.buildReversedKeymap(this.keyMap)
    this.stateKeys = this.addCmdToSkipKeys(this.stateKeys, cmdKey)
  }

  public getKeys() {
    return this.keyMap
  }

  public getKeysReversed() {
    return this.keyMapReversed
  }

  public getStateKeys() {
    return this.stateKeys
  }

  public getValue(key: string): number|number[] {
    const value = this.keyMap[key]
    if (!value) {
      throw new Error(`The key "${key}" is not supported`)
    }

    return value
  }

  private addCmdToSkipKeys(skipKeys: IStateKey[], cmd: number[]) {
    const _skipKeys = [...skipKeys]
    cmd.forEach(code => _skipKeys.push({ name: 'cmd', code: code }))
    return _skipKeys
  }

  private buildReversedKeymap(keymap) {
    const keyMapReversed: { [keyCode: number]: string } = {}

    // Build reversedMap (keys are values, values are keys)
    Object.keys(keymap).forEach(key => {
      let value = keymap[key]

      // Take into account multiple-values keys (such as cmd)
      if (Array.isArray(value)) {
        value.forEach(val => keyMapReversed[val] = key)
      } else {
        keyMapReversed[value] = key
      }
    })

    return keyMapReversed
  }
}

export const keyContainer = new KeyContainer() // Singleton instance