slt-js

0.2.0 verified Fri May 01 auth: no javascript

SLT (Script Localization Tool) transpiler for JavaScript that replaces localized keywords in ES (Spanish), FR (French), and IT (Italian) source files with canonical JavaScript keywords. Version 0.2.0, pre-1.0, with no scheduled release cadence. Differentiators: simple reference implementation with header-based language detection (#!slt <lang>), custom mapping support, and CLI. Limitations: not a full JS tokenizer, may mishandle regex literals; not production-ready.

Common errors

error slt-js: error: cannot read file 'nonexistent.js' ↓

cause File not found.

fix

Check file path and ensure the file exists.

error Error: No language header found. Use #!slt <lang> at the top of the file. ↓

cause Missing or malformed SLT header on first line.

fix

Add '#!slt es' (or fr/it) as the first line of the source file.

error slt-js: error: Invalid mapping file 'bad.json' ↓

cause JSON parse error or invalid structure.

fix

Ensure mapping file is valid JSON with key-value pairs: { "localized": "canonical" }.

Warnings

gotcha SLT header must be exactly at line 1, no leading whitespace. ↓

fix Ensure the file starts with '#!slt <lang>' on the first line, no BOM or spaces.

gotcha Transpiler is not token-aware and may modify strings or comments if they contain localized keywords. ↓

fix Avoid using localized keywords inside strings or comments, or use a full parser like @babel/parser.

gotcha Only three built-in languages: es, fr, it. ↓

fix Use --map to provide a custom mapping file for other languages.

Install

npm install slt-js

yarn add slt-js

pnpm add slt-js

Imports

slt-js (CLI)

wrong

npx slt-js <file> (does not expose programmatic API)

correct

slt-js <file> [options]

No programmatic API; only CLI usage.

Quickstart

Transpile a Spanish-localized JavaScript file to canonical JS using the CLI tool.

// example-esp.js
#!slt es
function saludar(nombre) {
  consola.escribir('Hola, ' + nombre);
}

// Install globally: npm install -g slt-js
// Transpile: slt-js example-esp.js -o example.js
// Output:
// function saludar(nombre) {
//   console.log('Hola, ' + nombre);
// }