Adds isAnagram algorithm in Javascript

[waghcwb]

Fixes #35

[shingz96]

Since Anagrams don't necessarily have to use all the letters, but they normally do, it will be nice if allow both scenarios

function isAnagram(word1, word2, useAll){
	//default need use all
	//Anagrams don't necessarily have to use all the letters, but they normally do.
	if(typeof useAll == "undefined" || typeof useAll != "boolean"){
		useAll = true;
	}
	
	//check string only
	if(typeof word1 != "string" && typeof word1 != "string"){
		throw Error("Invalid argument! Only String type is allow to compare!");
	}
	
	//normalise to array
	let arr1 = word1.replace(/\s/g, "").toLowerCase().split('').sort();
	let arr2 = word2.replace(/\s/g, "").toLowerCase().split('').sort();

	//check anagrams that must use exatcly all 
	if(useAll || arr1.length == arr2.length){
		return arr1.join('') == arr2.join('');
	}
	
	//determine which is part of another
	let whole = arr1.length > arr2.length ? arr1 : arr2;
	let part = arr2.length < arr1.length ? arr2 : arr1;
	
	for(let i = 0; i < whole.length; i++){
		let index = part.indexOf(whole[i]);
		part.splice(index,1);
	}
	
	return part.length == 0;
}

//example use
isAnagram('why','how') // expected output: false
isAnagram('funeral','real fun') // expected output: true
isAnagram('funeral','real funs') // expected output: false
isAnagram('funeral','real funs',false) // expected output: true

[waghcwb]

@shingz96,

Thank you, I've updated the code.