joshcanhelp · January 28, 2022 13:21 · Oct 21, 2016 · Oct 21, 2016
diff --git a/scrollTo.js b/scrollTo.js
@@ -12,25 +12,17 @@ module.exports = function (scrollTo, scrollDuration) {
 	if (typeof scrollTo === 'string') {
 
 		// Assuming this is a selector we can use to find an element
-
 		var scrollToObj = document.querySelector(scrollTo);
 
 		if (scrollToObj && typeof scrollToObj.getBoundingClientRect === 'function') {
-
 			scrollTo = window.pageYOffset + scrollToObj.getBoundingClientRect().top;
-
 		} else {
-
-			console.log(scrollTo);
 			throw 'error: No element found with the selector "' + scrollTo + '"';
 		}
-
 	} else if (typeof scrollTo !== 'number') {
 
 		// If it's nothing above and not an integer, we assume top of the window
-
 		scrollTo = 0;
-
 	}
 
 	// Set this a bit higher

diff --git a/scrollTo.js b/scrollTo.js
@@ -0,0 +1,115 @@
+//
+// Smooth scroll-to inspired by:
+// http://stackoverflow.com/a/24559613/728480
+//
+
+module.exports = function (scrollTo, scrollDuration) {
+
+	//
+	// Set a default for where we're scrolling to
+	//
+
+	if (typeof scrollTo === 'string') {
+
+		// Assuming this is a selector we can use to find an element
+
+		var scrollToObj = document.querySelector(scrollTo);
+
+		if (scrollToObj && typeof scrollToObj.getBoundingClientRect === 'function') {
+
+			scrollTo = window.pageYOffset + scrollToObj.getBoundingClientRect().top;
+
+		} else {
+
+			console.log(scrollTo);
+			throw 'error: No element found with the selector "' + scrollTo + '"';
+		}
+
+	} else if (typeof scrollTo !== 'number') {
+
+		// If it's nothing above and not an integer, we assume top of the window
+
+		scrollTo = 0;
+
+	}
+
+	// Set this a bit higher
+
+	var anchorHeightAdjust = 30;
+	if (scrollTo > anchorHeightAdjust) {
+		scrollTo = scrollTo - anchorHeightAdjust;
+	}
+
+	//
+	// Set a default for the duration
+	//
+
+	if ( typeof scrollDuration !== 'number' || scrollDuration < 0 ) {
+		scrollDuration = 1000;
+	}
+
+	// Declarations
+
+	var cosParameter = (window.pageYOffset - scrollTo) / 2,
+		scrollCount = 0,
+		oldTimestamp = window.performance.now();
+
+	function step(newTimestamp) {
+
+		var tsDiff = newTimestamp - oldTimestamp;
+
+		// Performance.now() polyfill loads late so passed-in timestamp is a larger offset
+		// on the first go-through than we want so I'm adjusting the difference down here.
+		// Regardless, we would rather have a slightly slower animation than a big jump so a good
+		// safeguard, even if we're not using the polyfill.
+
+		if (tsDiff > 100) {
+			tsDiff = 30;
+		}
+
+		scrollCount += Math.PI / (scrollDuration / tsDiff);
+
+		// As soon as we cross over Pi, we're about where we need to be
+
+		if (scrollCount >= Math.PI) {
+			return;
+		}
+
+		var moveStep = Math.round(scrollTo + cosParameter + cosParameter * Math.cos(scrollCount));
+		window.scrollTo(0, moveStep);
+		oldTimestamp = newTimestamp;
+		window.requestAnimationFrame(step);
+	}
+
+	window.requestAnimationFrame(step);
+};
+
+//
+// Performance.now() polyfill from:
+// https://gist.github.com/paulirish/5438650
+//
+
+(function () {
+
+	if ("performance" in window == false) {
+		window.performance = {};
+	}
+
+	Date.now = (Date.now || function () {  // thanks IE8
+		return new Date().getTime();
+	});
+
+	if ("now" in window.performance == false) {
+
+		var nowOffset = Date.now();
+
+		if (performance.timing && performance.timing.navigationStart) {
+			nowOffset = performance.timing.navigationStart
+		}
+
+		window.performance.now = function now() {
+			return Date.now() - nowOffset;
+		}
+	}
+
+})();