transpiler

1.2.0 verified Fri May 01 auth: no javascript maintenance

AST-based transpiler wrapper for Node.js, version 1.2.0 (last release unknown, appears stable but rarely updated). It provides a simple way to define node handlers that transform AST nodes into strings. Unlike full-featured compiler toolkits like Babel, it is focused on lightweight, minimal transpilation without dependencies. Supports overrides per transpile call.

Common errors

error TypeError: transpiler.transpile is not a function ↓

cause Imported the module incorrectly, e.g., const transpiler = require('transpiler'); instead of calling create().

fix

Use const transpiler = require('transpiler').create(spec); or destructure create.

error TypeError: node.left is undefined ↓

cause AST node missing expected properties or handler not receiving the full node structure.

fix

Ensure AST has the required fields (e.g., left, right).

error Error: Unknown node type 'XYZ' ↓

cause Transpiler spec does not define a handler for the node type 'XYZ'.

fix

Add a handler for that node type in the spec or in options overrides.

error RangeError: Maximum call stack size exceeded ↓

cause Recursive or circular AST structure causing infinite recursion in transpile.

fix

Check AST for cycles or ensure base cases in handlers.

Warnings

breaking In version 1.0.0, the 'transpile' method changed signature from (ast, options) to (ast, data, options). ↓

fix Update calls to pass null as second argument if no data is needed: transpile(ast, null, options).

gotcha Node handlers receive 'transpile' as second argument; easily confused with the instance's 'transpile' method. ↓

fix Inside handler, use the local 'transpile' function to compile child nodes, not the instance method.

gotcha The 'original' function in overrides refers to the default handler for that node; calling 'original(node)' without arguments may cause issues if the handler expects more parameters. ↓

fix Always pass the node to original: original(node).

gotcha Package is purely synchronous; cannot handle async transpilation steps. ↓

fix Use a different library if you need async; this one is synchronous only.

Install

npm install transpiler

yarn add transpiler

pnpm add transpiler

Imports

create

wrong

const transpiler = require('transpiler').create(spec);
// Also works but less consistent

correct

const { create } = require('transpiler');
const transpiler = create(spec);

Both forms work; destructuring is common in modern code.

transpiler instance

wrong

const myTranspiler = new Transpiler(spec); // No class export

correct

const myTranspiler = create(spec);
myTranspiler.transpile(ast);

No constructor exposed; use create() function.

transpile method

wrong

myTranspiler.transpile(ast, options); // Missing data param

correct

myTranspiler.transpile(ast, data, options);

Second argument must be data (or null), third is options.

Quickstart

Creates a basic arithmetic transpiler from AST spec and transpiles an expression.

const { create } = require('transpiler');

const spec = {
  nodes: {
    'EXPR': function(node, transpile) {
      return transpile(node.left) + ' ' + node.operator + ' ' + transpile(node.right);
    },
    'OPERAND': function(node) {
      return node.value;
    }
  }
};

const transpiler = create(spec);
const ast = {
  name: 'EXPR',
  left: { name: 'OPERAND', value: 21 },
  operator: '+',
  right: { name: 'OPERAND', value: 27 }
};

console.log(transpiler.transpile(ast)); // '21 + 27'