How to fix FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory in Node.js

node --max-old-space-size=4096 app.js

{
  "scripts": {
    "build": "node --max-old-space-size=4096 node_modules/.bin/next build",
    "test": "node --max-old-space-size=4096 node_modules/.bin/jest"
  }
}

export NODE_OPTIONS="--max-old-space-size=4096"
node app.js

echo 'export NODE_OPTIONS="--max-old-space-size=4096"' >> ~/.bashrc
source ~/.bashrc

set NODE_OPTIONS=--max-old-space-size=4096
node app.js

$env:NODE_OPTIONS="--max-old-space-size=4096"
node app.js

NODE_OPTIONS="--max-old-space-size=4096"

const fs = require('fs');

const data = fs.readFileSync('large-file.json', 'utf8');
const parsed = JSON.parse(data); // Can cause memory errors

const fs = require('fs');
const readline = require('readline');

const readStream = fs.createReadStream('large-file.txt');
const rl = readline.createInterface({
  input: readStream,
  crlfDelay: Infinity
});

rl.on('line', (line) => {
  // Process each line individually
  console.log(line);
});

const { parser } = require('stream-json');
const { streamArray } = require('stream-json/streamers/StreamArray');

const pipeline = fs.createReadStream('large-array.json')
  .pipe(parser())
  .pipe(streamArray());

pipeline.on('data', ({ value }) => {
  // Process each array element individually
  console.log(value);
});

setInterval(() => {
  const usage = process.memoryUsage();
  console.log(`Heap Used: ${Math.round(usage.heapUsed / 1024 / 1024)} MB`);
  console.log(`Heap Total: ${Math.round(usage.heapTotal / 1024 / 1024)} MB`);
}, 5000);

node --inspect app.js

// Bad
events.forEach(event => {
  eventEmitter.on(event, handler);
});

// Good
events.forEach(event => {
  eventEmitter.on(event, handler);
});
// Later, when done:
events.forEach(event => {
  eventEmitter.removeListener(event, handler);
});