JavaScript Snippet – Undo Camel Case

Probably due to it being so late, I was looking for code to uncamelize (undo camel-casing) any string. I came across what claimed to be a solution in PHP but unfortunately did nothing but lowercased my string. Therefore I decided to write my own solution:

function uncamelize(s) {
  return s.replace(/[A-Z]/g, '_$&').toLowerCase();
}

Believe it or not, the solution is that simple. Here is an example of using it:

An interesting thing to note about this uncamelize implementation is that it uses the $& pattern to reuse the substring matched by the regular expression. Even though this substring is commonly used it is documented as shown here.

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