spglsl

0.3.1 verified Fri May 01 auth: no javascript maintenance

spglsl (v0.3.1) is a WebGL GLSL minifier and compiler based on Google ANGLE. It preprocesses directives, removes whitespace, applies constant folding, and mangles non-exported functions and variable names. Optimized for js13k game jams and similar size-constrained WebGL projects, it is distributed as a precompiled WASM binary via npm, runs on Node.js (>=14.17.4), and includes Rollup/Vite plugins. Unlike other GLSL minifiers (e.g., glsl-minify), spglsl provides full ANGLE-based compilation validation and controllable mangling via globals map. Release cadence is low; last major update 2022.

Common errors

error Cannot find module 'spglsl' ↓

cause Package not installed or path incorrect.

fix

Run 'npm install spglsl' and ensure it's in node_modules.

error spglslAngleCompile is not a function ↓

cause Incorrect import (default import instead of named import).

fix

Use 'import { spglslAngleCompile } from "spglsl";'.

error error: no viable overloaded '=' ↓

cause Unsupported GLSL syntax (e.g., struct assignment).

fix

Rewrite using supported constructs or disable minify.

Warnings

breaking spglsl is WASM-based and may fail on Node.js <14.17.4 due to missing WebAssembly support. ↓

fix Upgrade Node.js to >=14.17.4.

gotcha Max call stack size exceeded error when processing very large shaders (e.g., >1000 lines) due to recursive AST visitor. ↓

fix Split shader into smaller files or increase Node.js --stack-size.

deprecated rollupPluginSpglsl is no longer maintained and may break with Rollup >=3. ↓

fix Use a custom plugin or fork.

Install

npm install spglsl

yarn add spglsl

pnpm add spglsl

Imports

spglslAngleCompile
wrong
```
const { spglslAngleCompile } = require('spglsl')
```
correct
```
import { spglslAngleCompile } from 'spglsl'
```
ESM import only; CJS require may work but is not officially supported.

rollupPluginSpglsl

wrong

import rollupPluginSpglsl from 'spglsl'

correct

import { rollupPluginSpglsl } from 'spglsl'

Named export, not default export.

SpglslAngleCompileOptions
```
import type { SpglslAngleCompileOptions } from 'spglsl'
```
TypeScript type import for options; not needed at runtime.

Quickstart

Minifies and mangles a GLSL fragment shader using spglsl, with renamed uniforms and varying.

import { spglslAngleCompile } from 'spglsl';
import { readFileSync } from 'fs';

async function main() {
  const result = await spglslAngleCompile({
    mainFilePath: 'shader.frag',
    mainSourceCode: readFileSync('shader.frag', 'utf8'),
    minify: true,
    mangle: true,
    mangle_global_map: { myUniform: 'u', myVarying: 'v' }
  });
  if (!result.valid) {
    console.error(result.infoLog);
    throw new Error('Compilation failed');
  }
  console.log(result.output);
}
main().catch(console.error);