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Single executable applications

Source Code: src/node_sea.cc

This feature allows the distribution of a Node.js application conveniently to a system that does not have Node.js installed.

Node.js supports the creation of single executable applications by allowing the injection of a JavaScript file into the node binary. During start up, the program checks if anything has been injected. If the script is found, it executes its contents. Otherwise Node.js operates as it normally does.

The single executable application feature only supports running a single embedded CommonJS file.

A bundled JavaScript file can be turned into a single executable application with any tool which can inject resources into the node binary.

Here are the steps for creating a single executable application using one such tool, postject:

1. Create a JavaScript file:

   $ echo 'console.log(`Hello, ${process.argv[2]}!`);' > hello.js copy

2. Create a copy of the node executable and name it according to your needs:

   $ cp $(command -v node) hello copy

3. Inject the JavaScript file into the copied binary by running postject with the following options:

   • hello - The name of the copy of the node executable created in step 2.
   • NODE_JS_CODE - The name of the resource / note / section in the binary where the contents of the JavaScript file will be stored.
   • hello.js - The name of the JavaScript file created in step 1.
   • --sentinel-fuse NODE_JS_FUSE_fce680ab2cc467b6e072b8b5df1996b2 - The fuse used by the Node.js project to detect if a file has been injected.
   • --macho-segment-name NODE_JS (only needed on macOS) - The name of the segment in the binary where the contents of the JavaScript file will be stored.

   To summarize, here is the required command for each platform:

   • On systems other than macOS:

     $ npx postject hello NODE_JS_CODE hello.js \
         --sentinel-fuse NODE_JS_FUSE_fce680ab2cc467b6e072b8b5df1996b2 copy

   • On macOS:

     $ npx postject hello NODE_JS_CODE hello.js \
         --sentinel-fuse NODE_JS_FUSE_fce680ab2cc467b6e072b8b5df1996b2 \
         --macho-segment-name NODE_JS copy

4. Run the binary:

   $ ./hello world
   Hello, world! copy

const { createRequire } = require('node:module');
require = createRequire(__filename); copy