jquery githubのeffects.jsを見ると、割り当て後に変数を変更する際に問題が発生します
ソース: https://github.com/jquery/jquery/blob/master/src/effects.js
注: .animate からアニメーション (作業馬) への割り当てとオブジェクトの作成に注意してください。
animate: function( prop, speed, easing, callback ) {
var empty = jQuery.isEmptyObject( prop ),
optall = jQuery.speed( speed, easing, callback ),
doAnimation = function() {
// Operate on a copy of prop so per-property easing won't be lost
var anim = Animation( this, jQuery.extend( {}, prop ), optall );
// Empty animations resolve immediately
if ( empty ) {
anim.stop( true );
}
};
return empty || optall.queue === false ?
this.each( doAnimation ) :
this.queue( optall.queue, doAnimation );
}
//effects.js でアニメーション化
function Animation( elem, properties, options ) {
var result,
index = 0,
length = animationPrefilters.length,
deferred = jQuery.Deferred().always( function() {
// don't match elem in the :animated selector
delete tick.elem;
}),
tick = function() {
var currentTime = fxNow || createFxNow(),
remaining = Math.max( 0, animation.startTime + animation.duration - currentTime ),
// archaic crash bug won't allow us to use 1 - ( 0.5 || 0 ) (#12497)
temp = remaining / animation.duration || 0,
percent = 1 - temp,
index = 0,
length = animation.tweens.length;
for ( ; index < length ; index++ ) {
animation.tweens[ index ].run( percent );
}
deferred.notifyWith( elem, [ animation, percent, remaining ]);
if ( percent < 1 && length ) {
return remaining;
} else {
deferred.resolveWith( elem, [ animation ] );
return false;
}
},
animation = deferred.promise({
elem: elem,
props: jQuery.extend( {}, properties ),
opts: jQuery.extend( true, { specialEasing: {} }, options ),
originalProperties: properties,
originalOptions: options,
startTime: fxNow || createFxNow(),
duration: options.duration,
tweens: [],
createTween: function( prop, end ) {
var tween = jQuery.Tween( elem, animation.opts, prop, end,
animation.opts.specialEasing[ prop ] || animation.opts.easing );
animation.tweens.push( tween );
return tween;
},
stop: function( gotoEnd ) {
var index = 0,
// if we are going to the end, we want to run all the tweens
// otherwise we skip this part
length = gotoEnd ? animation.tweens.length : 0;
for ( ; index < length ; index++ ) {
animation.tweens[ index ].run( 1 );
}
// resolve when we played the last frame
// otherwise, reject
if ( gotoEnd ) {
deferred.resolveWith( elem, [ animation, gotoEnd ] );
} else {
deferred.rejectWith( elem, [ animation, gotoEnd ] );
}
return this;
}
}),
props = animation.props;
propFilter( props, animation.opts.specialEasing );
for ( ; index < length ; index++ ) {
result = animationPrefilters[ index ].call( animation, elem, props, animation.opts );
if ( result ) {
return result;
}
}
createTweens( animation, props );
if ( jQuery.isFunction( animation.opts.start ) ) {
animation.opts.start.call( elem, animation );
}
jQuery.fx.timer(
jQuery.extend( tick, {
anim: animation,
queue: animation.opts.queue,
elem: elem
})
);
// attach callbacks from options
return animation.progress( animation.opts.progress )
.done( animation.opts.done, animation.opts.complete )
.fail( animation.opts.fail )
.always( animation.opts.always );
}
その結果、クロージャー内の変数にアクセスする見込みがほとんどないため、変更された変数でアニメーションを停止して再キューイングする必要があると思います(誰かが私を修正してください)