CODEWITHSUNDEEP
node.js
Mike
Mike

Reputation: 14586

Use of internal Node.js module vs. public npm-module

In order to keep the code clean I want to avoid using hard-coded values but use pre-defined constants such as HTTP status codes.

I can do it either with:

import {constants as httpConstants} from "http2";

res.sendStatus(httpConstants.HTTP_STATUS_INTERNAL_SERVER_ERROR);

or with an npm-package such as http-status-codes:

import {StatusCodes} from 'http-status-codes';

res.sendStatus(StatusCodes.INTERNAL_SERVER_ERROR);

Do I understand it correctly that if http2/constants is a Node.js built-in module which is widely used internally by Node.js, the import of http2/constants, which is quite big, should not affect the app performance since it is already is in use by Node.js?

Upvotes: 0

Views: 137

Answers (1)

raina77ow
raina77ow

Reputation: 106385

All the internal modules (including http2) are registered when Node starts. Quoting the source:

// A list of built-in modules. In order to do module registration
// in node::Init(), need to add built-in modules in the following list.
// Then in binding::RegisterBuiltinModules(), it calls modules' registration
// function. This helps the built-in modules are loaded properly when
// node is built as static library. No need to depend on the
// __attribute__((constructor)) like mechanism in GCC.
#define NODE_BUILTIN_STANDARD_MODULES(V)

So yes, I'd rather use that module in your case.

By the way, technically HTTP status codes are not even part of http2 module: they're stored in node_http_common.h file as set of macroses:

#define HTTP_STATUS_CODES(V)                                                  \
  V(CONTINUE, 100)                                                            \
  V(SWITCHING_PROTOCOLS, 101)                                                 \
  V(PROCESSING, 102)                                                          \
  V(EARLY_HINTS, 103)                                                         \
  V(OK, 200)                                                                  \
  // ...

... and, finally, are connected to http2 module constants prop in yet another series of #define statements:

#define V(name, _) NODE_DEFINE_CONSTANT(constants, HTTP_STATUS_##name);
  HTTP_STATUS_CODES(V)
#undef V

What's funny though is that there's another place in Node storing the same data reversed (status codes are keys, not values): it's http module. Source:

const STATUS_CODES = {
  100: 'Continue',                   // RFC 7231 6.2.1
  101: 'Switching Protocols',        // RFC 7231 6.2.2
  102: 'Processing',                 // RFC 2518 10.1 (obsoleted by RFC 4918)
  103: 'Early Hints',                // RFC 8297 2
  200: 'OK',                         // RFC 7231 6.3.1
  201: 'Created',                    // RFC 7231 6.3.2
  // ...

Upvotes: 1

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