How do I test replace method in mocha?

Question

I am very new to mocha and got stuck with testing below functionality. I have following string replace_underscore_with_hyphen . I am replacing this with replace-underscore-with-hyphen using below functionality.

const type = "replace_underscore_with_hyphen";
     type = type.replace(/_/ig, '-');

But please may I know how do I test this functionality in mocha.

Answer 1

You can test that final string contains hyphen, and doesn't underscores:

const replaceUnderscores = () => {
  const type = "replace_underscore_with_hyphen";
  return type.replace(/_/ig, '-');
}

it('should replace underscores with hyphen', () => {
  const replaced = replaceUnderscores();
  expect(replaced).not.toContain('_');
  expect(replaced).toContain('-');
});