Fix Error: ENOENT: no such file or directory, open '/app/config/settings.json' in Node.js

This error means Node.js tried to open a file that does not exist at the specified path. Common causes include wrong relative paths, missing files in Docker builds, or incorrect working directory assumptions. Fix it by using path.resolve with __dirname and verifying the file exists before reading.

Reading the Stack Trace

Here's what each line means:

• at Object.openSync (node:fs:603:3): Node's fs module tried to open the file synchronously but the OS reported the path does not exist.
• at loadConfig (src/config/loader.js:9:28): Your config loader at line 9 calls readFileSync with a path that does not resolve to an existing file.
• at Object.<anonymous> (src/index.js:4:18): The config is loaded at application startup on line 4 of index.js, so the app crashes immediately.

Common Causes

const fs = require('fs');
const config = JSON.parse(fs.readFileSync('./config/settings.json', 'utf8'));

# Dockerfile
FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY src/ ./src/
# Missing: COPY config/ ./config/

// File was renamed to app-config.json but code still references settings.json
const config = JSON.parse(fs.readFileSync('./config/settings.json', 'utf8'));

The Fix

Use path.resolve with __dirname to build an absolute path relative to the source file, not the working directory. Check that the file exists before reading it to produce a clear error message instead of a raw ENOENT.

const fs = require('fs');

function loadConfig() {
  const raw = fs.readFileSync('./config/settings.json', 'utf8');
  return JSON.parse(raw);
}

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

function loadConfig() {
  const configPath = path.resolve(__dirname, '../config/settings.json');

  if (!fs.existsSync(configPath)) {
    throw new Error(
      `Config file not found at ${configPath}. ` +
      `Ensure config/settings.json exists and is included in your build.`
    );
  }

  const raw = fs.readFileSync(configPath, 'utf8');
  return JSON.parse(raw);
}

Testing the Fix

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

jest.mock('fs');

const { loadConfig } = require('./loader');

describe('loadConfig', () => {
  it('reads config from the correct absolute path', () => {
    fs.existsSync.mockReturnValue(true);
    fs.readFileSync.mockReturnValue('{"port": 3000}');
    const config = loadConfig();
    expect(config.port).toBe(3000);
    expect(fs.readFileSync).toHaveBeenCalledWith(
      expect.stringContaining('config/settings.json'),
      'utf8'
    );
  });

  it('throws a descriptive error when file is missing', () => {
    fs.existsSync.mockReturnValue(false);
    expect(() => loadConfig()).toThrow('Config file not found');
  });
});

Run your tests:

npm test

Pushing Through CI/CD

git checkout -b fix/nodejs-file-not-found,git add src/config/loader.js src/config/__tests__/loader.test.js,git commit -m "fix: use absolute path for config loading and check existence",git push origin fix/nodejs-file-not-found

Your CI config should look something like this:

name: CI
on:
  pull_request:
    branches: [main]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: '20'
          cache: 'npm'
      - run: npm ci
      - run: npm test -- --coverage
      - run: npm run build

The Full Manual Process: 18 Steps

Here's every step you just went through to fix this one bug:

1. Notice the error alert or see it in your monitoring tool
2. Open the error dashboard and read the stack trace
3. Identify the file and line number from the stack trace
4. Open your IDE and navigate to the file
5. Read the surrounding code to understand context
6. Reproduce the error locally
7. Identify the root cause
8. Write the fix
9. Run the test suite locally
10. Fix any failing tests
11. Write new tests covering the edge case
12. Run the full test suite again
13. Create a new git branch
14. Commit and push your changes
15. Open a pull request
16. Wait for code review
17. Merge and deploy to production
18. Monitor production to confirm the error is resolved

Total time: 30-60 minutes. For one bug.

npm install bugstack-sdk

const { initBugStack } = require('bugstack-sdk')

initBugStack({ apiKey: process.env.BUGSTACK_API_KEY })

Deploying the Fix (Manual Path)

1. Verify the config file exists in the project and is committed to version control.
2. Update the Dockerfile to COPY config/ into the image if applicable.
3. Replace relative paths with __dirname-based absolute paths.
4. Run tests locally to confirm the fix.
5. Open a PR and merge after CI passes.

Frequently Asked Questions