pressure/src/adapters/adapter.js

Pressure is a lightweight JavaScript library for both Force Touch and 3D Touch through a single API.

/*
This is the base adapter from which all the other adapters extend.
*/
class Adapter {
  constructor(el, block, options) {
    this.el = el;
    this.block = block;
    this.options = options;
    this.pressed = false;
    this.deepPressed = false;
    this.nativeSupport = false;
    this.runningPolyfill = false;
    this.runKey = Math.random();
  }

  setPressed(boolean) {
    this.pressed = boolean;
  }

  setDeepPressed(boolean) {
    this.deepPressed = boolean;
  }

  isPressed() {
    return this.pressed;
  }

  isDeepPressed() {
    return this.deepPressed;
  }

  add(event, set) {
    this.el.addEventListener(event, set, false);
  }

  runClosure(method) {
    if(method in this.block) {
      // call the closure method and apply nth arguments if they exist
      this.block[method].apply(this.el, Array.prototype.slice.call(arguments, 1));
    }
  }

  fail(event, runKey) {
    if(Config.get('polyfill', this.options)) {
      if(this.runKey === runKey) {
        this.runPolyfill(event);
      }
    } else {
      this.runClosure('unsupported', event);
    }
  }

  bindUnsupportedEvent() {
    this.add(supportsTouch ? 'touchstart' : 'mousedown', (event) => this.runClosure('unsupported', event));
  }

  _startPress(event) {
    if(this.isPressed() === false) {
      this.runningPolyfill = false;
      this.setPressed(true);
      this.runClosure('start', event);
    }
  }

  _startDeepPress(event) {
    if(this.isPressed() && this.isDeepPressed() === false) {
      this.setDeepPressed(true);
      this.runClosure('startDeepPress', event);
    }
  }

  _changePress(force, event) {
    this.nativeSupport = true;
    this.runClosure('change', force, event);
  }

  _endDeepPress() {
    if(this.isPressed() && this.isDeepPressed()) {
      this.setDeepPressed(false);
      this.runClosure('endDeepPress');
    }
  }

  _endPress() {
    if(this.runningPolyfill === false){
      if(this.isPressed()){
        this._endDeepPress();
        this.setPressed(false);
        this.runClosure('end');
      }
      this.runKey = Math.random();
      this.nativeSupport = false;
    } else {
      this.setPressed(false);
    }
  }

  deepPress(force, event) {
    force >= 0.5 ? this._startDeepPress(event) : this._endDeepPress();
  }

  runPolyfill(event) {
    this.increment = Config.get('polyfillSpeedUp', this.options) === 0 ? 1 : 10 / Config.get('polyfillSpeedUp', this.options);
    this.decrement = Config.get('polyfillSpeedDown', this.options) === 0 ? 1 : 10 / Config.get('polyfillSpeedDown', this.options);
    this.setPressed(true);
    this.runClosure('start', event);
    if(this.runningPolyfill === false) {
      this.loopPolyfillForce(0, event);
    }
  }

  loopPolyfillForce(force, event) {
    if(this.nativeSupport === false){
      if(this.isPressed()) {
        this.runningPolyfill = true;
        force = force + this.increment > 1 ? 1 : force + this.increment;
        this.runClosure('change', force, event);
        this.deepPress(force, event);
        setTimeout(this.loopPolyfillForce.bind(this, force, event), 10);
      } else {
        force = force - this.decrement < 0 ? 0 : force - this.decrement;
        if(force < 0.5 && this.isDeepPressed()) {
          this.setDeepPressed(false);
          this.runClosure('endDeepPress');
        }
        if(force === 0) {
          this.runningPolyfill = false;
          this.setPressed(true);
          this._endPress();
        } else {
          this.runClosure('change', force, event);
          this.deepPress(force, event);
          setTimeout(this.loopPolyfillForce.bind(this, force, event), 10);
        }
      }
    }
  }
}