code: function gitDateOf(val) {
    let date = null;
  
    try {
      date = exec(`git log -1 --format=%cI ${val}`).toString();
    } catch (err) {
      return new Error(err);
    }
  
    return date.substring(0, date.indexOf('T'));
  }
docs: Date of a git value
  @param  {string} val     Value.
  @return {string}         Date.