Verify node version via npx.

check_node_version.js

const { exec } = require("child_process");
const {engines} = require('./package');

exec("npx check-node-version --package", (error, stdout) => {
    const requiredNodeVersion = engines.node;
    
    if (error) {
      console.error(stdout);

      exec("node --version", (error, stdout) => {
        if (error)        {
          throw Error(error);
        }
        const currentNodeVersion = stdout;
        const exactRequiredVersion = '10.24.1'

        const mess = `
        The current node version ${currentNodeVersion} does not satisfy the required version ${requiredNodeVersion}.
      
        Windows instructions to solve the issue...
      
        1. Install nvm: 
              Download the 'nvm-setup.zip', extract, execute 'nvm-setup.exe' and follow the instructions.
              https://github.com/coreybutler/nvm-windows/releases
        
        2. After installation, close your VS Code (or favorite editor) and re-open again to refresh the new system path.
        
        3. Check successful install of nvm:
                   cmd: nvm version
                output: 1.1.7 
      
        4. Select or install of nvm:
                     cmd: nvm use ${exactRequiredVersion}
                  failed: node v${exactRequiredVersion} (64-bit) is not installed.
                 success: Now using node v${exactRequiredVersion} (64-bit)
        
        5. If needed, install node v${exactRequiredVersion}
                     cmd: nvm install ${exactRequiredVersion}
                  output: Downloading node.js version ${exactRequiredVersion} (64-bit)... 
                          Complete
                          Creating C:\\Users\\61452\\AppData\\Roaming\\nvm\\temp
                          
                          Downloading npm version ${exactRequiredVersion}... Complete
                          Installing npm v${exactRequiredVersion}...
                          
                          Installation complete. If you want to use this version, type
                          
                          nvm use ${exactRequiredVersion}
        
        6. List all the node version
                    cmd: nvm list
                 output: 14.16.0
                         14.14.0
                         * ${exactRequiredVersion} (Currently using 64-bit executable)
        
        ---------------------------------------
      
        Mac and Linux can follow the instructions here to get nvm:
          https://github.com/nvm-sh/nvm
         `;
        
         // auto select correct version
         exec("nvm version", (error, stdout) => {
           if (error) new Error(mess);
           
           console.info(`nvm version:\n${stdout}`);

           exec("nvm list", (error, stdout) => {
            if (error) new Error(mess);
            
            console.info(`nvm list:\n${stdout}`);

            const nodeVersionsAvailable = stdout.split('\n')
                                                  .map(v => v.trim().replace('\n',''));
                                                  
            nodeVersionsAvailable.forEach(v => {
              if (v) {
                const major = v.substr(0, v.indexOf('.')) ;
                if (major.includes('* 10')) {
                  // already selected, nothing to do here.
                  return;
                }

                if (major.includes('10')){
                  // nvm use the node version
                  exec(`nvm use ${v}`, async (error, stdout) => {
                    if (error) new Error(mess);
                    console.info(`nvm use ${v}:\n${stdout}`);
                    // wait for the 1 second, otherwise the terminal does not fully register it is using a new node version.
                    // Detail: if you remove this line, it will switch to new node version but the terminal still executes as if it in the old node version
                    // ...and of course it will then fail. If you re-run npm run start, all will work.
                    // This little dirty HACK got me past this hurdle.
                    await sleep(1000);
                    return;
                  });
                }
              }
            });

            if (error) new Error(mess);
           });
         });
      });
      
    } else {
      console.log(`Node version check, ${requiredNodeVersion}, is satisfied...all is well :)\n`);
    }

});

const sleep = ms => {
  return new Promise(resolve => {
    setTimeout(resolve, ms);
  });
};