fromCamelCase

Converts a string from camelcase.

Use String.prototype.replace() to remove underscores, hyphens, and spaces and convert words to camelcase. Omit the second argument to use a default separator of _.

const fromCamelCase = (str, separator = "_") =>
  str
    .replace(/([a-z\d])([A-Z])/g, "$1" + separator + "$2")
    .replace(/([A-Z]+)([A-Z][a-z\d]+)/g, "$1" + separator + "$2")
    .toLowerCase();

fromCamelCase("someDatabaseFieldName", " "); // 'some database field name'
fromCamelCase("someLabelThatNeedsToBeCamelized", "-"); // 'some-label-that-needs-to-be-camelized'
fromCamelCase("someJavascriptProperty", "_"); // 'some_javascript_property'