Javascript difference between two words

Question

How do you detect the difference between two similar words?

For example:

• word compared to word, gives , as a variable
• this compared to .this gives . as a variable
• info compared to :info, gives : and , as a variable

In this case we always know which word is the longer one. And the actual word is always the same for the comparison. It's just that the longer one maybe has some extra characters.

I need to do this using javascript only.

• Nina Scholz: please add some more examples and their results.
• user1114: longer.replace(shorter, '')
• Praveen Kumar Purushothaman: What you are looking for is called Levenshtein Distance.
• Amy Neville: @PraveenKumar that sounds a bit intense - it's not possible with javascript?
• Praveen Kumar Purushothaman: @AmyNeville See my answer. :) It's possible. The link I sent you is JavaScript. What do you think it is then?

Answer 1

You could try checking for difference between the array of characters.

var shortStr = 'info';
var longStr = ':info,';
console.log(Array.from(longStr).filter(function(c) {
 return Array.from(shortStr).indexOf(c) === -1;
}));

• Praveen Kumar Purushothaman: Yea, as I said you, the first code you posted doesn't work. Arrow functions do not work consistently in all the browsers.

Answer 2

Also, there's a better way, check if the string is a sub-string, and then remove the sub-string from the main string:

function checkDiff(a, b) {
 var big = '', small = '';
 if (a.length > b.length) {
 big = a;
 small = b;
 } else {
 small = a;
 big = b;
 }
 if (big.indexOf(small) != -1) {
 return big.replace(small, "");
 } else {
 return false;
 }
}
alert(checkDiff("word", "word,"));
alert(checkDiff("this", ".this"));
alert(checkDiff("info", ":info,"));

I have added demo for all your cases. It returns the values as a single string, based on the place it has occurred. You can send the output as an array as well, using the .split() method.

function checkDiff(a, b) {
 var big = '', small = '';
 if (a.length > b.length) {
 big = a;
 small = b;
 } else {
 small = a;
 big = b;
 }
 if (big.indexOf(small) != -1) {
 console.log(big.replace(small, "").split(""));
 return big.replace(small, "").split("");
 } else {
 return false;
 }
}
alert(checkDiff("word", "word,"));
alert(checkDiff("this", ".this"));
alert(checkDiff("info", ":info,"));

• Amy Neville: is it possible to return the start and end variables separately? :0
• Praveen Kumar Purushothaman: @AmyNeville Added console.log as well to check in console if it works fine. And it does return the different values as an array, on the basis of the occurrence.
• Praveen Kumar Purushothaman: @AmyNeville Glad it helped. Would you wanna know more information? I mean, do you have any more questions for me?