Animate with hata framework

hata.animate.js

/*
Usage:
hata.animate( stepFunction, params );

Params:
* duration - animation time
* delay - pause between repeating
* type - type of delta incrementing
* delta - increment function
* done - functin after animation

Add new type:
hata.animTypes[ "newType" ] = function( x ) {};

Change default params:
hata.animParams[ paramName ] = 100;
*/

(function( hata ) {
	var methods = {
		
		animTypes: {
			normslow: function( x ) {
				return Math.sin( x * Math.PI / 2 );
			},
			slowslow: function( x ) {
				return ( 1 - Math.cos( x * Math.PI ) ) / 2;
			}
		},
	
		animParams: {
			duration: 200,
			delay: 10,
			type: "normslow",
			delta: function( x ) {
				return hata.animTypes[ this.type ]( x );
			},
			done: function() {}
		},
	
		animate: function( step, opts ) {
			var timer,
				start = new Date,
				opts = hata.extend({}, hata.animParams, opts ),
	
			timer = setInterval(function() {
				var progress = ( new Date - start ) / opts.duration;
	
				if ( progress > 1 ) {
					progress = 1;
				}
	
				step( opts.delta( progress ) );
	
				if ( progress === 1 ) {
					clearInterval( timer );
					opts.done.call( this );
				}
	
			}, opts.delay );
		}
	};
	
	hata.extend( hata, methods );
	
}( hata ));