lib/docs/router.js
function(path, handler) {
    var node = trie.define(path)[0];

    if (typeof handler !== 'function') {
      throw new Error('invalid handler');
    }

    node.handler = handler;
  }
function(path, handler) {
    var node = trie.define(path)[0];

    if (typeof handler !== 'function') {
      throw new Error('invalid handler');
    }

    node.handler = handler;
  }
function ( path , handler ) { var node = trie . define ( path ) [ 0 ] ; if ( typeof handler !== 'function' ) { throw new Error ( 'invalid handler' ) ; } node . handler = handler ; }
check and define routes
check and define routes