Search using JavaScript

binarysearch.js

//Binary Search
//Runtime - O(log n)
//Faster than Linear search
function binarySearch(arr, num) {
	//sort the array
	//arr.sort() modifies the original array
	arr.sort(function(a, b) {
		return a - b;
	});

	var lowLimit = 0,
		upLimit = arr.length - 1,
		middle = 0;

	while(lowLimit <= upLimit) {
        	middle = Math.floor((lowLimit + upLimit)/2);
		//console.log(middle);

		if(num === arr[middle]) {
			return middle; //match found, return
		} else if(num > arr[middle]) {
			lowLimit = middle + 1; //right half
        	} else {
			upLimit = middle - 1; //left half
        	}
	}
	return -1; //no match
} 

linearsearch.js

//Linear Search
//Worst Case Runtime - O(n)
//Slower than Binary search
function linearSearch(arr, num) {
	for(var i=0; i<arr.length; i++) {
		if(num === arr[i]) {
			return i; //match found, return the index
		}
	}
	return -1; //not found
}