How should the initialScreen parameter be handled

[KatieWoe]

For phetsims/qa#649. Related to #714. Seen on Win 10 Chrome.
The initialScreen=X query parameter seems to be handled differently for different simulations. For older sims, such as Acid-Base solutions, it highlights the X option on the home screen, and if X is invalid the sim starts with nothing highlighted but the sim is usable. In other sims, such as Area Model Introduction, it opens the sim to X page and if X is invalid the sim won't load and has a large number of console errors.

[KatieWoe]

Same difference can be seen with invalid screens inputs.

[jonathanolson]

Auto-scanning sim differences with the following:

const Maintenance = require( './js/common/Maintenance' );
const ReleaseBranch = require( './js/common/ReleaseBranch' );
const puppeteerEvaluate = require( './js/common/puppeteerEvaluate' );
const checkoutTarget = require( './js/common/checkoutTarget' );
const winston = require( 'winston' );

winston.default.transports.console.level = 'error';

( async () => {
  const releaseBranches = await ReleaseBranch.getMaintenanceBranches();

  for ( let releaseBranch of releaseBranches ) {
    console.log( `${releaseBranch.repo} ${releaseBranch.branch}` );
    try {
      await checkoutTarget( releaseBranch.repo, releaseBranch.branch, false );

      const numScreens = await puppeteerEvaluate( `http://localhost/${releaseBranch.repo}/${releaseBranch.repo}_en.html?brand=phet&ea`, () => {
        return phet.joist.sim.screens.filter( screen => screen !== phet.joist.sim.homeScreen ).length;
      }, {
        waitAfterLoad: 20000
      } );

      console.log( `  screens: ${numScreens}` );

      if ( numScreens >= 2 ) {
        const selectedScreenIndex = await puppeteerEvaluate( `http://localhost/${releaseBranch.repo}/${releaseBranch.repo}_en.html?brand=phet&ea&initialScreen=2`, () => {
          const currentScreen = phet.joist.sim.currentScreenProperty ? phet.joist.sim.currentScreenProperty.value : phet.joist.sim.screenProperty.value;

          const allScreens = [ phet.joist.sim.homeScreen, ...phet.joist.sim.screens.filter( screen => screen !== phet.joist.sim.homeScreen ) ];

          return Math.max( allScreens.indexOf( currentScreen ), 0 );
        }, {
          waitAfterLoad: 20000
        } );

        console.log( `  selected: ${selectedScreenIndex}` );
      }

      // await checkoutTarget( releaseBranch.repo, 'master', false );
    }
    catch ( e ) {
      console.log( e );
    }
  }
} )();

[jonathanolson]

Closing, handled in maintenance release deployment.