javascript - Difference between local and global require in RequireJS -

using requirejs, don't believe understand difference between following 2 different usages of 'require'. in case, talking browser, not node.js. 1 of questions is: can require dependencies synchronously on front-end using requirejs?

first there this:

    define(function(){           //below require global require of requirejs, aliased requirejs.           require(['module'],function(mod){             //mod loaded here             }        }); 

then there this:

   define(['require'],function(require){        require(['dep'],function(dep){  //require local not global            //dep loaded here          }       //now require subsequently called 'local' require      var dep = require('dependency'); //i doubt possible on front-end..or it?       }); 

i guess don't see purpose of using require argument define on front-end, there one?

my confusion arising because of example here:

http://requirejs.org/docs/api.html

relative module names inside define(): require("./relative/name") calls can happen inside define() function call, sure ask "require" dependency, relative name resolved correctly:

define(["require", "./relative/name"], function(require) {     var mod = require("./relative/name"); }); 

from above, can guess can make synchronous calls other modules requirejs on front-end if 1 module relative another?

likewise, example:

generate urls relative module: may need generate url relative module. so, ask "require" dependency , use require.tourl() generate url:

define(["require"], function(require) {     var cssurl = require.tourl("./style.css"); }); 

so, question is: difference between local require , global require? doesn't appear local require only/primarily commonjs modules.

all of these examples use asynchronous module loading, not synchronous. code looking @ bit confusing because seems synchronous, in reality not.

in example:

define(["require", "./relative/name"], function(require) {     var mod = require("./relative/name"); }); 

the asynchrony explicit. because module id './relative/name' in dependency array, function not called until has been (asynchronously) loaded. require call return module has (asynchronously) loaded.

in supported syntax, asynchrony hidden:

define(function(require) {     var mod = require("./relative/name"); }); 

but asynchronous. requirejs rewrites code contain dependency array 1 above. asynchrony get, despite appearances.

why useful , different? because can challenging match dozen members of array corresponding places in function turned variables. consider example docs:

define([ "require", "jquery", "blade/object", "blade/fn", "rdapi",          "oauth", "blade/jig", "blade/url", "dispatch", "accounts",          "storage", "services", "widgets/accountpanel", "widgets/tabbutton",          "widgets/addaccount", "less", "ostheme", "jquery-ui-1.8.7.min",          "jquery.textoverflow"], function (require,   $,        object,         fn,         rdapi,           oauth,   jig,         url,         dispatch,   accounts,           storage,   services,   accountpanel,           tabbutton,           addaccount,           less,   ostheme) {  }); 

another reason useful , differnt local require allows resolve relative module paths. lets define bunch of modules relative each other without explicitly specifying directory in, handy if directory might change.