Replace underscores with spaces and capitalize words

Since Lodash 3.1.0, there's a _.startCase([string='']) method that transforms any case into capitalized words (start case):

_.startCase('hello_world'); // returns 'Hello World'
_.startCase('hello-world'); // returns 'Hello World'
_.startCase('hello world'); // returns 'Hello World'

There are other useful methods in the String section of Lodash. Read the documentation here.

This should do the trick:

function humanize(str) {
  var i, frags = str.split('_');
  for (i=0; i<frags.length; i++) {
    frags[i] = frags[i].charAt(0).toUpperCase() + frags[i].slice(1);
  }
  return frags.join(' ');
}


console.log(humanize('humpdey_dumpdey'));
// > Humpdey Dumpdey

repl

http://repl.it/OnE

Fiddle:

http://jsfiddle.net/marionebl/nf4NG/

jsPerf:

Most test data: http://jsperf.com/string-transformations

All versions plus _.str: http://jsperf.com/string-transformations/3

These are two different tasks, so two different regexes is the best solution:

key = key.replace(/_/g, ' ').replace(/(?: |\b)(\w)/g, function(key) { return key.toUpperCase()});

To ensure even all capital words is processed. You can add .toLowerCase() before the very first .replace:

console.log('TESTING_WORD'.toLowerCase().replace(/_/g, ' ')
.replace(/(?: |\b)(\w)/g, function(key, p1) {
    return key.toUpperCase();    
}));