loadNodeVersionFromPackage.js

const chalk = require('chalk');
const semver = require('semver');

function chalkLog(color, message) {
  console.log(chalk[color](message));
}

function loadNodeVersionFromPackageJson() {
  chalkLog('green', 'Loading...  loadNodeVersionFromPackageJson from ~/.zshrc');
  const packageJsonPath = `${process.cwd()}/package.json`;

  // Check if package.json file exists.
  if (fs.existsSync(packageJsonPath)) {
    const packageJson = require(packageJsonPath);
    const nodeVersion = packageJson.engines?.node;

    if (!nodeVersion) {
      chalkLog('yellow', 'package.json has no .engines.node version defined');
      return;
    }

    const validRange = semver.validRange(nodeVersion);

    if (!validRange) {
      chalkLog('yellow', `Invalid node version range: ${nodeVersion}`);
      return;
    }

    const versions = Object.keys(nvm_ls());

    let matchedVersion = null;

    for (const version of versions) {
      if (semver.satisfies(version, validRange)) {
        matchedVersion = version;
        break;
      }
    }

    if (matchedVersion) {
      chalkLog('green', `This directory has a package.json file with .engines.node (${nodeVersion})`);
      nvm_use(matchedVersion);
      // Record modification of node version.
      process.env.NODE_VERSION_MODIFIED = true;
      return;
    }

    chalkLog('yellow', `No matching node version found for range: ${nodeVersion}`);
    return;
  }

  if (process.env.NODE_VERSION_MODIFIED) {
    // Revert to default node version.
    chalkLog('green', 'Reverting to default node version.');
    nvm_use('default');
    process.env.NODE_VERSION_MODIFIED = false;
  }
}

loadNodeVersionFromPackage.test.ts

const { loadNodeVersionFromPackageJson } = require('./loadNodeVersionFromPackageJson');

describe('loadNodeVersionFromPackageJson', () => {
  afterEach(() => {
    jest.clearAllMocks();
  });

  it('should use the version specified in package.json', () => {
    const packageJson = {
      engines: {
        node: '14.15.3',
      },
    };
    jest.mock(`${process.cwd()}/package.json`, () => packageJson, { virtual: true });
    const nvmUseSpy = jest.spyOn(global.console, 'log');
    loadNodeVersionFromPackageJson();
    expect(nvmUseSpy).toHaveBeenCalledWith(expect.stringContaining('Now using node version 14.15.3'));
  });

  it('should print a warning if package.json has no engines.node version defined', () => {
    const packageJson = {};
    jest.mock(`${process.cwd()}/package.json`, () => packageJson, { virtual: true });
    const consoleWarnSpy = jest.spyOn(global.console, 'warn');
    loadNodeVersionFromPackageJson();
    expect(consoleWarnSpy).toHaveBeenCalledWith(expect.stringContaining('package.json has no .engines.node version defined'));
  });

  it('should print a warning if package.json .engines.node version has special characters', () => {
    const packageJson = {
      engines: {
        node: '~14.15.3',
      },
    };
    jest.mock(`${process.cwd()}/package.json`, () => packageJson, { virtual: true });
    const consoleWarnSpy = jest.spyOn(global.console, 'warn');
    loadNodeVersionFromPackageJson();
    expect(consoleWarnSpy).toHaveBeenCalledWith(expect.stringContaining('nvm does not support special characters (^, >, ~)'));
  });

  it('should print a warning if package.json .engines.node version is not compatible with nvm', () => {
    const packageJson = {
      engines: {
        node: '>=16.0.0 <17.0.0 || >=18.0.0 <19.0.0',
      },
    };
    jest.mock(`${process.cwd()}/package.json`, () => packageJson, { virtual: true });
    const consoleWarnSpy = jest.spyOn(global.console, 'warn');
    loadNodeVersionFromPackageJson();
    expect(consoleWarnSpy).toHaveBeenCalledWith(expect.stringContaining('is not compatible with nvm'));
  });

  it('should print a warning if package.json .engines.node version has wildcard', () => {
    const packageJson = {
      engines: {
        node: '14.x',
      },
    };
    jest.mock(`${process.cwd()}/package.json`, () => packageJson, { virtual: true });
    const consoleWarnSpy = jest.spyOn(global.console, 'warn');
    loadNodeVersionFromPackageJson();
    expect(consoleWarnSpy).toHaveBeenCalledWith(expect.stringContaining('is not compatible with nvm'));
  });

  it('should use the major version specified in package.json', () => {
    const packageJson = {
      engines: {
        node: '>=14',
      },
    };
    jest.mock(`${process.cwd()}/package.json`, () => packageJson, { virtual: true });
    const nvmUseSpy = jest.spyOn(global.console, 'log');
    loadNodeVersionFromPackageJson();
    expect(nvmUseSpy).toHaveBeenCalledWith(expect.stringContaining('Now using node version 14'));
  });
});