/**
 * Converts an underline-separated string to camel case.
 * e.g. underlineToHump('hello_word') => 'helloWord'
 *
 * @param {string} target - The underline-separated string to convert.
 * @return {string} The camel case version of the input string.
 */
export function underlineToHump(target: string) {
  let isStartUnderline = true
  let prefixStr = null
  let str = ''
  for (let i = 0; i < target.length; i++) {
    if (
      target[i] === '_' &&
      /[a-z]/.test(target[i + 1]) &&
      !isStartUnderline &&
      prefixStr !== '_'
    ) {
      i++
      str += target[i].toUpperCase()
      continue
    }
    prefixStr = target[i]
    if (isStartUnderline && target[i] !== '_') {
      isStartUnderline = false
    }
    str += target[i]
  }
  return str
}