【ソース読み取り】解析Anime(JSアニメーションライブラリ)の核心(2)

// anime  
function anime(params){
  
  //   instance        
  let instance = createNewInstance(params);
  
  //   API            
  instance.play = function() {}
  
  //    startTime   engineTime(  )
   instance.tick = function(t) {}
   
  //    engineTime    ，      (  )
  function setInstanceProgress(engineTime) {}
  
  //              (  )
  function setAnimationsProgress(insTime){}

  //       time        
  instance.seek = function(time) {}
  //   API   
  instance.pause = function() {}
  //   API   
  instance.reverse = function() {}
  //   API reset
  instance.reset = function() {}
  //   API     
  instance.restart = function() {}
  /*...*/
  return instance
}

//              
function setAnimationsProgress(insTime) {
  /* ... */
  //   while                   (       )
  while (i < animationsLength) {
      /* ... */
    //                       
    const elapsed = minMaxValue(insTime - tween.start - tween.delay, 0, tween.duration) / tween.duration;
    //           
    const eased = isNaN(elapsed) ? 1 : tween.easing(elapsed, tween.elasticity);
    /* ... */
    //           
    for (let n = 0; n < toNumbersLength; n++) {
      let value;
      const toNumber = tween.to.numbers[n];
      const fromNumber = tween.from.numbers[n];
      if (!tween.isPath) {
        //         
        value = fromNumber + (eased * (toNumber - fromNumber));
      } else {
        //   SVG path  
        value = getPathProgress(tween.value, eased * toNumber);
      }
      /* ... */
      numbers.push(value);
    }
         /* ... */
        if (!isNaN(n)) {
          //      '135.546'+'px'
          if (!b) {
            progress += n + ' ';
          } else {
            progress += n + b;
          }
        }
    /* ... */
    //      'translateX('+'135.546px'+')`
    setTweenProgress[anim.type](animatable.target, anim.property, progress, transforms, animatable.id);
    anim.currentValue = progress;
    i++;
  }
  //     ，  target  
  const transformsLength = Object.keys(transforms).length;
  if (transformsLength) {
    for (let id = 0; id < transformsLength; id++) {
      if (!transformString) {
        const t = 'transform';
        //      
        transformString = (getCSSValue(document.body, t) ? t : `-webkit-${t}`);
      }
      //   style
      instance.animatables[id].target.style[transformString] = transforms[id].join(' ');
    }
  }
  //             
  instance.currentTime = insTime;
  //     
  instance.progress = (insTime / instance.duration) * 100;
}

//       time        
instance.seek = function(time) {
  setInstanceProgress(adjustTime(time));
}

//   API   
instance.pause = function() {
  const i = activeInstances.indexOf(instance);
  //   activeInstances   engine         
  if (i > -1) activeInstances.splice(i, 1);
  instance.paused = true;
}

//   API   
instance.reverse = function() {
  toggleInstanceDirection();
  startTime = 0;
  lastTime = adjustTime(instance.currentTime);
}

//   API     
instance.restart = function() {
  instance.pause();
  instance.reset();
  instance.play();
}

//   API reset
instance.reset = function() {
  const direction = instance.direction;
  const loops = instance.loop;
  //     ,     
  instance.currentTime = 0;
  instance.progress = 0;
  instance.paused = true;
  instance.began = false;
  instance.completed = false;
  instance.reversed = direction === 'reverse';
  instance.remaining = direction === 'alternate' && loops === 1 ? 2 : loops;
  setAnimationsProgress(0);
  for (let i = instance.children.length; i--; ){
    instance.children[i].reset();
  }
}