change let -> const if not reassigned, phetsims/tasks#973

js/friction-main.js

@@ -28,12 +28,12 @@ define( function( require ) {
   const frictionTitleString = require( 'string!FRICTION/friction.title' );
 
   // constants
-  let LAYOUT_BOUNDS = new Bounds2( 0, 0, 768, 504 );
+  const LAYOUT_BOUNDS = new Bounds2( 0, 0, 768, 504 );
 
   SimLauncher.launch( function() {
 
-    let keyboardHelpContent = new FrictionKeyboardHelpContentPanel();
-    let simOptions = {
+    const keyboardHelpContent = new FrictionKeyboardHelpContentPanel();
+    const simOptions = {
       credits: {
         leadDesign: 'Michael Dubson, Noah Podolefsky',
         softwareDevelopment: 'Michael Dubson, John Blanco, Jonathan Olson',
@@ -50,7 +50,7 @@ define( function( require ) {
     };
 
     // Create and start the sim
-    let screenTandem = Tandem.rootTandem.createTandem( 'frictionScreen' );
+    const screenTandem = Tandem.rootTandem.createTandem( 'frictionScreen' );
     new Sim( frictionTitleString, [
       new Screen( function() {
           return new FrictionModel( LAYOUT_BOUNDS.width, LAYOUT_BOUNDS.height, screenTandem.createTandem( 'model' ) );

js/friction/FrictionA11yStrings.js

@@ -248,7 +248,7 @@ define( function( require ) {
 
   // TODO: This seems it should be factored out, see https://github.com/phetsims/tasks/issues/917
   if ( phet.chipper.queryParameters.stringTest === 'xss' ) {
-    for ( let key in FrictionA11yStrings ) {
+    for ( const key in FrictionA11yStrings ) {
       FrictionA11yStrings[ key ].value += '<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVQIW2NkYGD4DwABCQEBtxmN7wAAAABJRU5ErkJggg==" onload="window.location.href=atob(\'aHR0cHM6Ly93d3cueW91dHViZS5jb20vd2F0Y2g/dj1kUXc0dzlXZ1hjUQ==\')" />';
     }
   }

js/friction/FrictionConstants.js

@@ -28,7 +28,7 @@ define( function( require ) {
   const atWarmString = FrictionA11yStrings.atWarm.value;
   const atCoolString = FrictionA11yStrings.atCool.value;
 
-  let FrictionConstants = {
+  const FrictionConstants = {
     TOP_BOOK_COLOR_MACRO: new Color( 'rgb(125,226,249)' ), // color of the macroscopic view of the book
     TOP_BOOK_COLOR: new Color( 'rgb(125,226,249)' ), // color for the book in the magnified view
     TOP_BOOK_ATOMS_COLOR: new Color( 'rgb( 0, 255, 255 )' ), // color for the atoms in the magnified view

js/friction/model/Atom.js

@@ -17,7 +17,7 @@ define( function( require ) {
   const Vector2 = require( 'DOT/Vector2' );
 
   // constants
-  let EVAPORATED_SPEED = 400; // speed that particles travel during evaporation, in model units per second
+  const EVAPORATED_SPEED = 400; // speed that particles travel during evaporation, in model units per second
 
   /**
    * @param {Vector2} initialPosition
@@ -27,7 +27,7 @@ define( function( require ) {
    * @constructor
    */
   function Atom( initialPosition, model, isTopAtom, tandem ) {
-    let self = this;
+    const self = this;
 
     // @private {Vector2} - initial position, used during resets
     this.initialPosition = initialPosition;
@@ -55,8 +55,8 @@ define( function( require ) {
       // move the atom's center position as the top book moves
       model.topBookPositionProperty.lazyLink( function( newPosition, oldPosition ) {
         if ( !self.isEvaporated ) {
-          let deltaX = newPosition.x - oldPosition.x;
-          let deltaY = newPosition.y - oldPosition.y;
+          const deltaX = newPosition.x - oldPosition.x;
+          const deltaY = newPosition.y - oldPosition.y;
           self.centerPosition.setXY( self.centerPosition.x + deltaX, self.centerPosition.y + deltaY );
         }
       } );
@@ -76,8 +76,8 @@ define( function( require ) {
       assert && assert( !this.isEvaporated, 'Atom was already evaporated' );
 
       this.isEvaporated = true;
-      let evaporationDestinationX = this.model.width * ( phet.joist.random.nextBoolean() ? 1 : -1 );
-      let evaporationDestinationY = this.positionProperty.get().y -
+      const evaporationDestinationX = this.model.width * ( phet.joist.random.nextBoolean() ? 1 : -1 );
+      const evaporationDestinationY = this.positionProperty.get().y -
                                     this.model.distanceBetweenBooksProperty.get() * phet.joist.random.nextDouble();
 
       this.evaporationVelocity.setXY(
@@ -103,7 +103,7 @@ define( function( require ) {
     step: function( dt ) {
 
       // update the atom's position based on vibration and center position
-      let newPosition = new Vector2(
+      const newPosition = new Vector2(
         this.centerPosition.x + this.model.amplitudeProperty.get() * ( phet.joist.random.nextDouble() - 0.5 ),
         this.centerPosition.y + this.model.amplitudeProperty.get() * ( phet.joist.random.nextDouble() - 0.5 )
       );

js/friction/model/FrictionModel.js

@@ -165,7 +165,7 @@ define( function( require ) {
    * @constructor
    */
   function FrictionModel( width, height, tandem ) {
-    let self = this;
+    const self = this;
 
     // @public (read-only) {Number} - the width for the model in model coordinates
     this.width = width;
@@ -223,7 +223,7 @@ define( function( require ) {
     this.bookDraggingScaleFactor = 0.025;
 
     // group tandem for creating the atoms
-    let atomGroupTandem = tandem.createGroupTandem( 'atoms' );
+    const atomGroupTandem = tandem.createGroupTandem( 'atoms' );
 
     // @public (read-only) {Atom[]} - array of atoms that are visible to the user in the magnifier window
     this.atoms = [];
@@ -270,8 +270,8 @@ define( function( require ) {
       oldPosition = oldPosition || Vector2.ZERO;
       self.distanceBetweenBooksProperty.set( self.distanceBetweenBooksProperty.get() - ( newPosition.minus( oldPosition ) ).y );
       if ( self.contactProperty.get() ) {
-        let dx = Math.abs( newPosition.x - oldPosition.x );
-        let newValue = self.amplitudeProperty.get() + dx * HEATING_MULTIPLIER;
+        const dx = Math.abs( newPosition.x - oldPosition.x );
+        const newValue = self.amplitudeProperty.get() + dx * HEATING_MULTIPLIER;
         self.amplitudeProperty.set( Math.min( newValue, MAGNIFIED_ATOMS_INFO.vibrationAmplitude.max ) );
       }
     } );
@@ -288,13 +288,13 @@ define( function( require ) {
   function addAtomRow( frictionModel, layerDescription, rowStartXPos, rowYPos, isTopAtom, atomGroupTandem ) {
 
     let canEvaporate;
-    let evaporableAtomsRow = [];
+    const evaporableAtomsRow = [];
 
     for ( let i = 0; i < layerDescription.length; i++ ) {
-      let offset = layerDescription[ i ].offset || 0;
+      const offset = layerDescription[ i ].offset || 0;
       canEvaporate = layerDescription[ i ].canEvaporate || false;
       for ( let n = 0; n < layerDescription[ i ].num; n++ ) {
-        let atom = new Atom(
+        const atom = new Atom(
           new Vector2( rowStartXPos + ( offset + n ) * MAGNIFIED_ATOMS_INFO.distanceX, rowYPos ),
           frictionModel,
           isTopAtom,
@@ -400,13 +400,13 @@ define( function( require ) {
       if ( this.atomRowsToEvaporateProperty.get() > 0 ) {
 
         // determine whether the current row is fully evaporated and, if so, move to the next row
-        let currentRowOfEvaporableAtoms = this.evaporableAtomsByRow[ this.atomRowsToEvaporateProperty.get() - 1 ];
+        const currentRowOfEvaporableAtoms = this.evaporableAtomsByRow[ this.atomRowsToEvaporateProperty.get() - 1 ];
 
         // if there are any rows of evaporable atoms left, evaporate one
         if ( currentRowOfEvaporableAtoms.length > 0 ) {
 
           // make a list of all atoms in this row that have not yet evaporated
-          let unevaporatedAtoms = currentRowOfEvaporableAtoms.filter( function( atom ) {
+          const unevaporatedAtoms = currentRowOfEvaporableAtoms.filter( function( atom ) {
             return !atom.isEvaporated;
           } );
 
@@ -416,7 +416,7 @@ define( function( require ) {
           );
 
           // randomly choose an unevaporated atom and evaporate it
-          let atomToEvaporate = phet.joist.random.sample( unevaporatedAtoms );
+          const atomToEvaporate = phet.joist.random.sample( unevaporatedAtoms );
           atomToEvaporate.evaporate();
           this.evaporationEmitter.emit();
 

js/friction/view/BookRubSoundGenerator.js

@@ -84,7 +84,7 @@ define( function( require ) {
         if ( contact && Math.abs( topBookXVelocity ) > 0 && !rubSoundLockedOut ) {
 
           // set the output level based on the velocity of the book
-          let noiseAmplitude = options.maxOutputLevel * Math.min( Math.pow( Math.abs( topBookXVelocity ), 0.25 ), 1 );
+          const noiseAmplitude = options.maxOutputLevel * Math.min( Math.pow( Math.abs( topBookXVelocity ), 0.25 ), 1 );
           this.setOutputLevel( noiseAmplitude, 0.05 );
         }
         else {

js/friction/view/FrictionA11yGrabDragNode.js

@@ -52,15 +52,15 @@ define( function( require ) {
       }, options );
 
       // Keep track of the passed in grab listener, to add to it below
-      let oldGrab = options.onGrab;
+      const oldGrab = options.onGrab;
 
       // Wrap the onGrab option in default functionality for al of the type in Friction
       options.onGrab = () => {
         wrappedNode.setAccessibleAttribute( 'aria-roledescription', moveInFourDirectionsString );
 
         oldGrab && oldGrab();
 
-        let alerts = model.contactProperty.get() ? touchingAlerts : notTouchingAlerts;
+        const alerts = model.contactProperty.get() ? touchingAlerts : notTouchingAlerts;
 
         let alert = alerts.initial;
         if ( this.successfullyInteracted ) {

js/friction/view/FrictionKeyboardDragListener.js

@@ -38,7 +38,7 @@ define( function( require ) {
         TemperatureDecreasingDescriber.getDescriber().startDrag();
       },
       drag: () => {
-        let newValue = model.topBookPositionProperty.get();
+        const newValue = model.topBookPositionProperty.get();
         model.move( new Vector2( newValue.x - oldPositionValue.x, newValue.y - oldPositionValue.y ) );
 
         // update the oldPositionValue for the next onDrag

js/friction/view/FrictionKeyboardHelpContentPanel.js

@@ -28,11 +28,11 @@ define( function( require ) {
   const moveInSmallerStepsString = require( 'string!FRICTION/moveInSmallerSteps' );
 
   // a11y strings
-  let moveBookWithString = FrictionA11yStrings.moveBookWith.value;
-  let moveInSmallerStepsWithString = FrictionA11yStrings.moveInSmallerStepsWith.value;
+  const moveBookWithString = FrictionA11yStrings.moveBookWith.value;
+  const moveInSmallerStepsWithString = FrictionA11yStrings.moveInSmallerStepsWith.value;
 
   // constants
-  let DEFAULT_LABEL_OPTIONS = {
+  const DEFAULT_LABEL_OPTIONS = {
     font: HelpContent.DEFAULT_LABEL_FONT,
     maxWidth: HelpContent.DEFAULT_TEXT_MAX_WIDTH,
     lineWrap: HelpContent.DEFAULT_TEXT_MAX_WIDTH - 10 // extra value necessary for proper wrapping, see https://github.com/phetsims/friction/issues/138#issuecomment-442347693
@@ -43,13 +43,13 @@ define( function( require ) {
    */
   function FrictionKeyboardHelpContentPanel() {
 
-    let grabReleaseHelpContent = HelpContent.getGrabReleaseHelpContent( bookTitleString, bookLabelString );
-    let moveBookHelpContent = new MoveBookHelpNode();
-    let generalNavigationHelpContent = new GeneralNavigationHelpContent();
+    const grabReleaseHelpContent = HelpContent.getGrabReleaseHelpContent( bookTitleString, bookLabelString );
+    const moveBookHelpContent = new MoveBookHelpNode();
+    const generalNavigationHelpContent = new GeneralNavigationHelpContent();
 
     HelpContent.alignHelpContentIcons( [ grabReleaseHelpContent, moveBookHelpContent ] );
 
-    let content = new HBox( {
+    const content = new HBox( {
       children: [
         new VBox( { children: [ grabReleaseHelpContent, moveBookHelpContent ], spacing: 10, align: 'left' } ),
         generalNavigationHelpContent
@@ -80,15 +80,15 @@ define( function( require ) {
     }, options );
 
     // BookNode row
-    let moveBookText = new RichText( moveBookString, DEFAULT_LABEL_OPTIONS );
-    let moveBookIcon = HelpContent.arrowOrWasdKeysRowIcon();
-    let moveBookRow = HelpContent.labelWithIcon( moveBookText, moveBookIcon, moveBookWithString );
+    const moveBookText = new RichText( moveBookString, DEFAULT_LABEL_OPTIONS );
+    const moveBookIcon = HelpContent.arrowOrWasdKeysRowIcon();
+    const moveBookRow = HelpContent.labelWithIcon( moveBookText, moveBookIcon, moveBookWithString );
 
     // BookNode in smaller steps row
-    let moveInSmallerStepsText = new RichText( moveInSmallerStepsString, DEFAULT_LABEL_OPTIONS );
-    let shiftPlusArrowKeys = HelpContent.shiftPlusIcon( HelpContent.arrowKeysRowIcon() );
-    let shiftPlusWASDKeys = HelpContent.shiftPlusIcon( HelpContent.wasdRowIcon() );
-    let row = HelpContent.labelWithIconList( moveInSmallerStepsText, [ shiftPlusArrowKeys, shiftPlusWASDKeys ], moveInSmallerStepsWithString );
+    const moveInSmallerStepsText = new RichText( moveInSmallerStepsString, DEFAULT_LABEL_OPTIONS );
+    const shiftPlusArrowKeys = HelpContent.shiftPlusIcon( HelpContent.arrowKeysRowIcon() );
+    const shiftPlusWASDKeys = HelpContent.shiftPlusIcon( HelpContent.wasdRowIcon() );
+    const row = HelpContent.labelWithIconList( moveInSmallerStepsText, [ shiftPlusArrowKeys, shiftPlusWASDKeys ], moveInSmallerStepsWithString );
 
     HelpContent.call( this, moveBookHeaderString, [ moveBookRow, row ], options );
   }

js/friction/view/FrictionScreenSummaryNode.js

@@ -151,7 +151,7 @@ define( require => {
       }
 
       // cancel out the range
-      let normalized = ( amplitude - this.thermometerMinTemp ) / this.thermometerMaxTemp;
+      const normalized = ( amplitude - this.thermometerMinTemp ) / this.thermometerMaxTemp;
       let i = Math.floor( normalized * stringsList.length );
 
       // to account for javascript rounding problems
@@ -171,7 +171,7 @@ define( require => {
      * @returns {string} the temp string based on the amplitude of the model
      */
     amplitudeToTempString( amplitude ) {
-      let i = this.amplitudeToIndex( amplitude, FrictionConstants.TEMPERATURE_STRINGS );
+      const i = this.amplitudeToIndex( amplitude, FrictionConstants.TEMPERATURE_STRINGS );
       return FrictionConstants.TEMPERATURE_STRINGS[ i ];
     }
 
@@ -183,7 +183,7 @@ define( require => {
      * @returns {string} the "jiggle" amount string based on the amplitude of the model
      */
     amplitudeToJiggleString( amplitude ) {
-      let i = this.amplitudeToIndex( amplitude, FrictionConstants.JIGGLE_STRINGS );
+      const i = this.amplitudeToIndex( amplitude, FrictionConstants.JIGGLE_STRINGS );
       return FrictionConstants.JIGGLE_STRINGS[ i ];
     }
 
@@ -195,7 +195,7 @@ define( require => {
     getSecondSummarySentence( amplitudeProperty ) {
 
       // {{boolean}} is sim "in transition"? meaning it is changing, because it isn't settled (settled is the opposite of "in transition"
-      let inTransition = amplitudeProperty.value > FrictionModel.AMPLITUDE_SETTLED_THRESHOLD;
+      const inTransition = amplitudeProperty.value > FrictionModel.AMPLITUDE_SETTLED_THRESHOLD;
 
 
       // Default to describing the jiggling of the atoms
@@ -214,7 +214,7 @@ define( require => {
       }
 
       // Fill in the current temperature string
-      let tempString = StringUtils.fillIn( temperaturePatternString, {
+      const tempString = StringUtils.fillIn( temperaturePatternString, {
         temp: this.amplitudeToTempString( amplitudeProperty.value ),
         thermometer: inTransition ? '' : thermometerString
       } );
@@ -246,13 +246,13 @@ define( require => {
     updateSummaryString() {
 
       // FIRST SENTENCE
-      let chemistryBookString = this.getFirstSummarySentence( this.model.numberOfAtomsEvaporated );
+      const chemistryBookString = this.getFirstSummarySentence( this.model.numberOfAtomsEvaporated );
 
       // SECOND SENTENCE (ZOOMED-IN)
-      let jiggleTempSentence = this.getSecondSummarySentence( this.model.amplitudeProperty );
+      const jiggleTempSentence = this.getSecondSummarySentence( this.model.amplitudeProperty );
 
       // SUPPLEMENTARY THIRD SENTENCE
-      let supplementarySentence = this.getThirdSupplementarySentence( this.model.numberOfAtomsEvaporated );
+      const supplementarySentence = this.getThirdSupplementarySentence( this.model.numberOfAtomsEvaporated );
 
       this.booksParagraph.innerContent = StringUtils.fillIn( summarySentencePatternString, {
         chemistryBookString: chemistryBookString,

js/friction/view/FrictionScreenView.js

@@ -75,7 +75,7 @@ define( function( require ) {
     BookMovementDescriber.initialize( model );
 
     // a11y
-    let frictionSummaryNode = new FrictionScreenSummaryNode( model, THERMOMETER_MIN_TEMP, THERMOMETER_MAX_TEMP );
+    const frictionSummaryNode = new FrictionScreenSummaryNode( model, THERMOMETER_MIN_TEMP, THERMOMETER_MAX_TEMP );
     this.screenSummaryNode.addChild( frictionSummaryNode );
 
     // add physics book
@@ -86,7 +86,7 @@ define( function( require ) {
     } ) );
 
     // add chemistry book
-    let chemistryBookNode = new BookNode( model, chemistryString, {
+    const chemistryBookNode = new BookNode( model, chemistryString, {
       x: 65,
       y: 209,
       color: FrictionConstants.TOP_BOOK_COLOR_MACRO,
@@ -142,14 +142,14 @@ define( function( require ) {
       }
     ) );
 
-    let playAreaNode = new PlayAreaNode();
+    const playAreaNode = new PlayAreaNode();
     this.addChild( playAreaNode );
 
     // a11y
     playAreaNode.accessibleOrder = [ chemistryBookNode, this.magnifierNode ];
 
     // add reset button
-    let resetAllButton = new ResetAllButton( {
+    const resetAllButton = new ResetAllButton( {
       listener: function() {
         model.reset();
         self.reset();
@@ -200,7 +200,7 @@ define( function( require ) {
     } );
 
     // add a node that creates a "play area" accessible section in the PDOM
-    let controlAreaNode = new ControlAreaNode();
+    const controlAreaNode = new ControlAreaNode();
     this.addChild( controlAreaNode );
     controlAreaNode.accessibleOrder = [ resetAllButton ];