old_contents: 'use strict';
  
  if ('HEROKU' in process.env || ('DYNO' in process.env && process.env.HOME === '/app')) {
  
    const pkg = require('../package.json');
    const ChildProcess = require('child_process');
  
  
    let deps = pkg.devDependencies;
    let packages = "";
  
    Object.keys(deps).forEach((key) => {
      packages += `${key}@${deps[key]} `; // note space at end to separate entries
    });
  
    try {
      console.time("install");
      console.log("starting npm install of dev dependencies");
      ChildProcess.execSync(`npm install ${packages}`);
      console.timeEnd("install");
  
      console.time("build");
      console.log("starting npm build");
      ChildProcess.execSync(`npm run build:all`);
      console.timeEnd("build");
  
      console.time("uninstall");
      console.log("starting npm uninstall of dev dependencies");
      ChildProcess.execSync(`npm uninstall ${packages}`);
      console.timeEnd("uninstall");
    }
    catch (err) {
      console.error(err.message);
    }
  } else {
    console.log("Not Heroku, skipping postinstall build");
  }
new_contents: 'use strict';
  
  if ('HEROKU' in process.env || ('DYNO' in process.env && process.env.HOME === '/app')) {
  
    const pkg = require('../package.json');
    const ChildProcess = require('child_process');
  
  
    let deps = pkg.devDependencies;
    let packages = "";
  
    Object.keys(deps).forEach((key) => {
      packages += `${key}@${deps[key]} `; // note space at end to separate entries
    });
  
    try {
      console.time("install");
      console.log("starting npm install of dev dependencies");
      ChildProcess.execSync(`npm install ${packages}`);
      console.timeEnd("install");
  
      console.time("build");
      console.log("starting npm build");
      ChildProcess.execSync(`npm run build`);
      console.timeEnd("build");
  
      console.time("uninstall");
      console.log("starting npm uninstall of dev dependencies");
      ChildProcess.execSync(`npm uninstall ${packages}`);
      console.timeEnd("uninstall");
    }
    catch (err) {
      console.error(err.message);
    }
  } else {
    console.log("Not Heroku, skipping postinstall build");
  }
subject: Fix Heroku script (calling npm build)