Procedure for creating Node JS add ons

Below is how to setup the boiler plate code

mkdir test-addon
cd test-addon
git init
npm init

Now install the dependencies

npm install node-gyp --save-dev
npm install node-addon-api

node-gyp is the toolchain to compile the addons.
node-addon-api is a helper project as described earlier that will make writing C++ addons easier.


Couple of files that are important during the process are:

1. Bindings.gyp
2. package.json

Below is a sample content for this

Binding.gyp

{
    "targets": [{
        "target_name": "testaddon",
        "cflags!": [ "-fno-exceptions" ],
        "cflags_cc!": [ "-fno-exceptions" ],
        "sources": [
            "cppsrc/main.cpp"
        ],
        'include_dirs': [
            "<!@(node -p \"require('node-addon-api').include\")"
        ],
        'libraries': [],
        'dependencies': [
            "<!(node -p \"require('node-addon-api').gyp\")"
        ],
        'defines': [ 'NAPI_DISABLE_CPP_EXCEPTIONS' ]
    }]
}

package.json

{
  "name": "test-addon",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "gypfile": true,
  "scripts": {
    "build": "node-gyp rebuild",
    "clean": "node-gyp clean"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "node-gyp": "^3.7.0"
  },
  "dependencies": {
    "node-addon-api": "^1.3.0"
  }
}


Just to note, gypfile:true should be present here

Now having these files set up, compilation of the modules can be done in the below steps

npm run build

This will generate the testaddon.node file in the release folder


The add on can be used like this below

const testAddon = require('./build/Release/testaddon.node');
console.log('addon',testAddon);
module.exports = testAddon;


binding.gyp file contains all the files that need to be compiled and all the include files / libraries that the project will be using. If you notice we have added cppsrc/main.cpp file as our source file.


References:
https://medium.com/@atulanand94/beginners-guide-to-writing-nodejs-addons-using-c-and-n-api-node-addon-api-9b3b718a9a7f