Combine Two strings together

Question

I am trying to combine two strings together, but have any duplicates inside be replaces. I'm thinking string1 would supersede string2.

So if I have:

str1 = 'user { id name } roles { id name }';
str2 = 'user { roles match } permissions { id role_id }';

I would like to end up with:

'user { roles match } roles { id name } permissions { id role_id }'

I tried doing:

str1.replace(/[a-z]* {.*}/g, str2)

But this ends up replacing the first string with the second string.

Is this possible to do?

Answer 1

This might be a little overkill for what you need, but it should be pretty flexible and robust if you need to extend it or handle more possibilities.

 str1 = 'user { id name } roles { id name }'; str2 = 'user { roles match } permissions { id role_id }'; //Return an object containing the key and object parts of a string //getParts(str1) -> {user: '{ id name }', roles: '{ id name }'} function getParts(s) { var out = {}; var re = /([az]+) ({.*?})/gi; match = re.exec(s); while (match) { out[match[1]] = match[2]; match = re.exec(s); } return out; } //Takes in the parts object created by getParts and returns a space //separated string. Exclude is an array of strings to exclude from the result. //makeString(getParts(str1), ['user']) -> 'roles {id name}' function makeString(parts, exclude) { if (typeof exclude === 'undefined') { exclude = []; } var out = []; for (var key in parts) { if (!parts.hasOwnProperty(key)) { continue; } if (exclude.indexOf(key) !== -1) { continue; } out.push(key + ' ' + parts[key]); } return out.join(' '); } //Combines two strings in the desired format, with s2 keys taking precedence //in case of any duplicates function combine(s1, s2) { var p1 = getParts(s1); var p2 = getParts(s2); return makeString(p1, Object.keys(p2)) + ' ' + makeString(p2); } console.log(combine(str1, str2));