Check for current Node Version

I need to programmatically access the current node version running in a library I am writing. Can't seem to find this in the docs.

Try to look at process.version property.

process.version.match(/^v(\d+\.\d+)/)[1]

if process.version is 'v0.11.5', then get 0.11 .

Actually it would be better to use process.versions object which provides a lot of versions for the different node components. Example:

{
  http_parser: '2.5.2',
  node: '4.4.3',
  v8: '4.5.103.35',
  uv: '1.8.0',
  zlib: '1.2.8',
  ares: '1.10.1-DEV',
  icu: '56.1',
  modules: '46',
  openssl: '1.0.2g'
}

Use semver to compare process.version:

const semver = require('semver');

if (semver.gte(process.version, '0.12.18')) {
  ...
}

If you need to only check for the major version, you can use this quick-and-dirty snippet:

const NODE_MAJOR_VERSION = process.versions.node.split('.')[0];
if (NODE_MAJOR_VERSION < 12) {
  throw new Error('Requires Node 12 (or higher)');
}

Notes:

• process.versions.node is easier to work with than process.version, as you do not have to worry about whether the version starts with a leading v.
• If you still need to distinguish between ancient versions (e.g., 0.10 and 0.12), this will not work, as they will all be considered version "0".

I refined alsotang's answer a bit to compare versions:

const m = process.version.match(/(\d+)\.(\d+)\.(\d+)/);
const [major, minor, patch] = m.slice(1).map(_ => parseInt(_));

To perform an assertion, do it like this:

if (major >= 13 || (major >= 12 && minor >= 12)) {
    console.log("NodeJS is at least v12.12.0. It is safe to use fs.opendir!");
}

This can be shortened to a one-liner to use in bash:

NODE_VERSION=$(node -e "const v = process.version.match(/(\\d+)\.(\\d+)\.(\\d+)/).slice(1).map(_ => parseInt(_)); console.log(v[0] >= 13 || (v[0] >= 12 && v[1] >= 12))")
if $NODE_VERSION -eq "true" ;
then
    echo "NodeJS is at least v12.12.0."
fi

or PowerShell:

$nodeVersion = $(node -e "const v = process.version.match(/(\d+)\.(\d+)\.(\d+)/).slice(1).map(_ => parseInt(_)); console.log(v[0] >= 13 || (v[0] >= 12 && v[1] >= 12))")
if ($nodeVersion -eq "true") {
    Write-Host "NodeJS is at least v12.12.0."
}

I had the similar issue with my codebase. I wanted to know the current NodeJs version I am going to use to run my server at runtime. For that, I wrote a code which can be run before starting the Server using npm run start script. Found below code helpful from this question.

'use strict';
const semver = require('semver');
const engines = require('./package').engines;
const nodeVersion = engines.node;

// Compare installed NodeJs version with required NodeJs version.
if (!semver.satisfies(process.version, nodeVersion)) {
  console.log(`NodeJS Version Check: Required node version ${nodeVersion} NOT SATISFIED with current version ${process.version}.`);
  process.exit(1);
} else {
  console.log(`NodeJS Version Check: Required node version ${nodeVersion} SATISFIED with current version ${process.version}.`);
}

My package.json looks like this:

{
  "name": "echo-server",
  "version": "1.0.0",
  "engines": {
    "node": "8.5.0",
    "npm": "5.3.0"
  },
  "description": "",
  "main": "index.js",
  "scripts": {
    "check-version" : "node checkVersion.js",
    "start-server" : "node app.js"
    "start" : "npm run check-version && npm run start-server",
    "test": "npm run check-version && echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "bluebird": "^3.5.1",
    "express": "^4.16.3",
    "good-guy-http": "^1.10.3",
    "semver": "^5.5.0"
  }
}

Do run npm install command before you run npm run start command to run your project.

If you access node js running environments, there are 2 main entries: (one simeple, one detail)

• process.version will give you:

'v10.16.0'

• process.versions will give you:

{ http_parser: '2.8.0',
  node: '10.16.0',
  v8: '6.8.275.32-node.52',
  uv: '1.28.0',
  zlib: '1.2.11',
  brotli: '1.0.7',
  ares: '1.15.0',
  modules: '64',
  nghttp2: '1.34.0',
  napi: '4',
  openssl: '1.1.1b',
  icu: '64.2',
  unicode: '12.1',
  cldr: '35.1',
  tz: '2019a' }

also instead of writing this whole as suggested by @alsotang

Number(process.version.match(/^v(\d+\.\d+)/)[1])

(not saying this is a bad solution).

you can simply write

parseFloat(process.versions.node); it is versions (plural) not version

to get same or (similar) result and is easy to read