node.js - Do I need to 'require' a file if it is already required by another file -

i have 3 files

b requires a

c requires (b , a)

in scenario c needs require a? doubt because b requires , when c requires b should requires a.

so want sure whether c needs explicitly require or not.

upon same situation, when required explicitly :

i found following error :

module.js:340     throw err;     ^ error: cannot find module 'a'     @ function.module._resolvefilename (module.js:338:15)     @ function.module._load (module.js:280:25)     @ module.require (module.js:364:17)     @ require (module.js:380:17)     @ object.<anonymous> (/users/topi/controller.js:3:13)     @ module._compile (module.js:456:26)     @ object.module._extensions..js (module.js:474:10)     @ module.load (module.js:356:32)     @ function.module._load (module.js:312:12)     @ module.require (module.js:364:17) 

why so?

in cases, yes. each module needs reference module needs require() independently.

why so?

when use:

var = require('./a'); 

this declares a local variable current module, evaluated within own closure. why modules have exports allow them specify "public" api.

it can suggested each module must list dependencies, such c depending on a , b.

// c.js var = require('./a'); var b = require('./b'); 

but, use exports pass-along 1 module through -- e.g. a through b:

// b.js var = exports.a = require('./a'); 

// c.js var b = require('./b');  console.log(b.a); 

and, technically, attach a global. though, shouldn't. doing typically considered code smell.