Function debuglog

lib/internal/util/debuglog.js:87–138

(set, cb)

// that may be loaded before these run time states are allowed to
// be accessed.
function debuglog(set, cb) {
  function init() {
    set = StringPrototypeToUpperCase(set);
    enabled = testEnabled(set);
  }
  let debug = (...args) => {
    init();
    // Only invokes debuglogImpl() when the debug function is
    // called for the first time.
    debug = debuglogImpl(enabled, set);
    if (typeof cb === 'function') {
      ObjectDefineProperty(debug, 'enabled', {
        __proto__: null,
        get() {
          return enabled;
        },
        configurable: true,
        enumerable: true,
      });
      cb(debug);
    }
    switch (args.length) {
      case 1: return debug(args[0]);
      case 2: return debug(args[0], args[1]);
      default: return debug(...new SafeArrayIterator(args));
    }
  };
  let enabled;
  let test = () => {
    init();
    test = () => enabled;
    return enabled;
  };
  const logger = (...args) => {
    // Improve performance when debug is disabled, avoid calling `new SafeArrayIterator(args)`
    if (enabled === false) return;
    switch (args.length) {
      case 1: return debug(args[0]);
      case 2: return debug(args[0], args[1]);
      default: return debug(...new SafeArrayIterator(args));
    }
  };
  ObjectDefineProperty(logger, 'enabled', {
    __proto__: null,
    get() {
      return test();
    },
    configurable: true,
    enumerable: true,
  });
  return logger;
}

function pad(value) {
  return StringPrototypePadStart(`${value}`, 2, '0');