Question

Curious if I could get an example of a simple hash function in javascript as I am not sure what type of algorithm to use. I dont want the whole program just the function. Also if there could be some explanation of each line that would be great.

Answer 1

Let us consider the one of the simple hashing algorithm. Given a string the resultant hash of the function should be

hash = s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1] where s is a string s[0] is a character at 0th position of string and n is the length of string. 

And here we need to ensure that output shouldnt be more than 32 bit.

Here is the javascript function below;

function simpleHash(str){
len = str.length; // len variable now contains str length
hash = 0; // initialising hash variable to 0
for(i=1; i<=len; i++){ // looping all over the length of str
char = str.charCodeAt((i-1)); // getting character at i-1 position of string
hash += char*Math.pow(31,(len-i)); // raising its value to 32^(len-1) and appending result to hash
hash = hash & hash; // this is javascript limitation to force to 32 bits if it crosses 32 bits
}
return hash; // finally we are returning the obtained hash value to callee function
}

console.log(simpleHash("CheggAnswer")); // to output the hash value in console

If we try to console the value of SimpleHash("CheggAnswer") below is the output results in console which is provided for proof of work. Output we get is 1041930555.