src/cal-heatmap.js
function(d) {
		"use strict";

		var f = this.options.weekStartOnMonday === true ? d3.time.format("%W"): d3.time.format("%U");
		return f(d);
	}
function(d) {
		"use strict";

		var f = this.options.weekStartOnMonday === true ? d3.time.format("%W"): d3.time.format("%U");
		return f(d);
	}
function ( d ) { "use strict" ; var f = this . options . weekStartOnMonday === true ? d3 . time . format ( "%W" ) : d3 . time . format ( "%U" ) ; return f ( d ) ; }
Return the week number of the year
Monday as the first day of the week
@return int	Week number [0-53]
Return the week number of the year Monday as the first day of the week