'use strict'; | |
module.exports = function (str, sep) { | |
if (typeof str !== 'string') { | |
throw new TypeError('Expected a string'); | |
} | |
sep = typeof sep === 'undefined' ? '_' : sep; | |
return str | |
.replace(/([a-z\d])([A-Z])/g, '$1' + sep + '$2') | |
.replace(/([A-Z]+)([A-Z][a-z\d]+)/g, '$1' + sep + '$2') | |
.toLowerCase(); | |
}; |