binary searchy matchy thingy

bsmt.js

(function() {
    			
	//	Given an array of values, find all exact matches.
	//	If no matches are found, find the closest match.
	//
	//	Returns an array of indices where matches occur
	//	If no exact match, a closest match is performed and returned as an array with one element
	//
	function search(values, desired) {

		var low = 0, high = values.length, result = [];

		while (low < high) {
			var mid = (low + high) >>> 1;

			values[mid] < desired
				? low = mid + 1
				: high = mid;
		}

		if (values[low] == desired) {
			result.push(low);
			
			// because it's an ordered list, just check onwards
			while(values[++low] === desired) {
				result.push(low);
			}
		}

		if (result.length > 0) {
			return result;
		}

		if (values[low] !== desired) {
			var diff = [values[low - 1], values[low]].reduce(function(memo, val) {
				var d1 = Math.abs(memo - desired);
				var d2 = Math.abs(val - desired);
				return d1 > d2 ? val : memo;
			});
			low = values.indexOf(diff);
		}

		return [low];
	}

	// tests
	var f = search([60,72,100,120,180], 100);
	var g = search([60,72,100,100,100,120,180], 100);
	var h = search([60,72,100,100,100,120,180], 60);
	var i = search([60,72,100,100,100,120,180], 180);
	var j = search([60,72,100,100,100,120,180], 170);
	var k = search([60,72,100,100,100,120,180], 65);
	var l = search([90,100,400,400,600,700], 200);
	var m = search([90,100,201,400,600,700], 200);
	
	console.log('f: ' + (f.length == 1 && f[0] == 2));
	console.log('g: ' + (g.length == 3 && g[0] == 2 && g[1] == 3 && g[2] == 4));
	console.log('h: ' + (h.length == 1 && h[0] == 0));
	console.log('i: ' + (i.length == 1 && i[0] == 6));
	console.log('j: ' + (j.length == 1 && j[0] == 6));
	console.log('k: ' + (k.length == 1 && k[0] == 0));
	console.log('l: ' + (l.length == 1 && l[0] == 1));
	console.log('m: ' + (m.length == 1 && m[0] == 2));
	
})();