serpack/runtime

The output generated by serpack includes various functions and helper scripts that ensure smooth execution of JavaScript scripts.
However, redeclaring helpers that already exist leads to increased file size and inefficiency.

To address this issue, you can omit the declaration of these helpers.
Instead, a separate runner is required to execute the compiled file.

#Compilation

import { compile } from 'serpack';
 
compile('src/index.ts', { runtime: true });

#Execution

To run the compiled module, use createRuntime to create a runtime environment and execute it.

import { createRuntime } from 'serpack/runtime';
 
const runtime = createRuntime('./output.js');
 
runtime.execute();

Simply pass the output path of the module compiled with the runtime option into createRuntime, and it will handle execution.

#Runtime Instance

#runtime.execute() --runtime

Execute the compiled module and get its exported value.

export default {
  apple: '🍎',
};

#runtime.createExternalModule() --runtime

Create virtual module.

import { name } from 'hello'; // module "hello" is a virtual module.
 
console.log(`Hello ${name}!`); // Hello World!

#runtime.require() --runtime node-only

Same: #createRequire()

#APIs

#env()

Load runtime environment variables.

import { env } from 'serpack/runtime';
 
console.log(env().target === 'node'); // type target = "browser" | "node"

#createRequire() node-only

Receive a virtual module and create a requirement.

import { createRequire } from 'serpack/runtime';
 
// createRequire is node-only feature
process.env.__RUNTIME__ = JSON.stringify({ target: 'node' });
 
const $require = createRequire({
  1: (__serpack_require__, require, module, exports) => {
    module.exports = 'Hello World';
  },
});
 
console.log($require('sp:1')); // Hello World

#Size Reduction

• target: @playground/typescript/pages/index.ts

553 KB

Size reduced by 60%.

#Troubleshooting

#Error: Cannot find module '@swc/helpers'

This error occurs because the @swc/helpers package is damaged or missing.

npm i --save-dev @swc/helpers

#TypeError: __serpack_require__ is not a function

An error occurred because the target is not set to node. This can occur when you create a require using createRequire().

process.env.__RUNTIME__ = JSON.stringify({ target: 'node' });
// or window.__RUNTIME__ = JSON.stringify({ target: 'node' });

Change runtime environment to node.