gcode-parser

2.2.0 verified Sat May 09 auth: no javascript

G-code parser for Node.js, current stable version 2.2.0. Maintained as part of the cncjs ecosystem. Provides synchronous and asynchronous parsing of G-code strings, lines, files, and streams. Key differentiators: supports line modes (original, stripped, compact) and flatten option for word representation. Used widely in CNC toolpath generation and visualization.

Common errors

error TypeError: parser.parseFile is not a function ↓

cause Using ES module import syntax with require or missing installation.

fix

Use const parser = require('gcode-parser'); and run in Node.js CJS environment.

error TypeError: Cannot read property '0' of undefined ↓

cause Assuming words are always present in result, but empty lines return { words: [] }.

fix

Check for empty array before accessing elements: if (result.words.length > 0) { ... }

error TypeError: callback is not a function ↓

cause Calling parseFile without a second argument (callback) or passing a non-function.

fix

Always provide a callback: parser.parseFile('file.nc', (err, result) => { ... });

Warnings

gotcha parseFile and parseString callbacks accept (err, results) but also return an EventEmitter. Not handling both can lead to missed events. ↓

fix Use callback for results, and attach listeners for 'data' or 'end' if needed.

gotcha parseLine with options object: lineMode and flatten should be passed as second argument. Omitting options uses defaults. ↓

fix Correct: parser.parseLine('G0 X0', { flatten: true }); Incorrect: parser.parseLine('G0 X0', true);

gotcha Result words are arrays of [letter, number] in non-flatten mode. Forgetting this can cause type errors. ↓

fix Access word[0] for letter and word[1] for value, or use flatten: true to get strings like 'G0'.

Install

npm install gcode-parser

yarn add gcode-parser

pnpm add gcode-parser

Imports

default

wrong

import parser from 'gcode-parser';

correct

const parser = require('gcode-parser');

CJS module; ESM import not supported.

parseLine
wrong
```
parseLine('G0 X0 Y0');
```
correct
```
parser.parseLine('G0 X0 Y0');
```
Must call on the parser object.
parseFile
wrong
```
parser.parseFile('file.nc');
```
correct
```
parser.parseFile('file.nc', callback);
```
Callback is required; returns an EventEmitter with 'data' and 'end' events.
parseStringSync
```
const results = parser.parseStringSync('G0 X0');
```
Synchronous variant available for parseString and parseFile.

Quickstart

Demonstrates parsing a single line, async file parsing, and sync string parsing.

const fs = require('fs');
const parser = require('gcode-parser');

// Parse a single line
console.log(parser.parseLine('G0 X0 Y0'));
// => { line: 'G0 X0 Y0', words: [ [ 'G', 0 ], [ 'X', 0 ], [ 'Y', 0 ] ] }

// Parse a file asynchronously
parser.parseFile('example.nc', (err, results) => {
  if (err) throw err;
  console.log(results);
});

// Parse a string synchronously
const str = fs.readFileSync('example.nc', 'utf8');
const results = parser.parseStringSync(str);
console.log(results);