handle stringFactor === 1 properly, improve doc, cleanup, phetsims/ch…

…ipper#1319

js/DynamicStringTest.ts

@@ -6,20 +6,21 @@
  *
  * @author Sam Reid (PhET Interactive Simulations)
  * @author Marla Schulz (PhET Interactive Simulations)
+ * @author Chris Malley (PixelZoom, Inc.)
  */
 
 import { localizedStrings } from '../../chipper/js/getStringModule.js';
 import Utils from '../../dot/js/Utils.js';
 import joist from './joist.js';
 
-// key codes
+// keyCodes
 const LEFT_ARROW = 37;
 const UP_ARROW = 38;
 const RIGHT_ARROW = 39;
 const DOWN_ARROW = 40;
 const SPACE_BAR = 32;
 
-// Random words of different lengths that can be cycled through
+// Words of different lengths that can be cycled through
 const WORD_SOURCE = 'Sometimes when Hippopotomonstrosesquippedaliophobia want lyrics you turn to Shakespeare like ' +
                     'the following text copied from some work ' +
                     'To be or not to be that is the question ' +
@@ -30,10 +31,23 @@ const WORD_SOURCE = 'Sometimes when Hippopotomonstrosesquippedaliophobia want ly
 export default class DynamicStringTest {
   public static init(): void {
 
+    const words = WORD_SOURCE.split( ' ' );
+
     // How much to increase or decrease the length of the string
     let stringFactor = 1;
+
+    // An integer that assists in indexing into words.
     let stride = 0;
-    const words = WORD_SOURCE.split( ' ' );
+
+    function doubleStrings(): void {
+      stringFactor = stringFactor * 2;
+      applyToAllStrings( stringFactor );
+    }
+
+    function halveStrings(): void {
+      stringFactor = Math.max( stringFactor * 0.5, 0.01 );
+      applyToAllStrings( stringFactor );
+    }
 
     function setStride( newStride: number ): void {
 
@@ -46,29 +60,21 @@ export default class DynamicStringTest {
       }
 
       stride = newStride;
-      console.log( 'stride = ' + stride );
+      console.log( `stride = ${stride}` );
 
       localizedStrings.forEach( ( localizedString, index ) => {
         localizedString.property.value = words[ ( index + stride ) % words.length ];
       } );
     }
 
-    function doubleStrings(): void {
-      stringFactor = stringFactor * 2;
-      applyToStrings( stringFactor );
-    }
-
-    function halveStrings(): void {
-      stringFactor = Math.max( stringFactor * 0.5, 0.01 );
-      applyToStrings( stringFactor );
-    }
-
     function reset(): void {
+
       stringFactor = 1;
       console.log( `stringFactor = ${stringFactor}` );
+      applyToAllStrings( stringFactor );
+
       stride = 0;
       console.log( `stride = ${stride}` );
-      localizedStrings.forEach( localizedString => localizedString.restoreInitialValue( 'en' ) );
     }
 
     window.addEventListener( 'keydown', event => {
@@ -92,38 +98,43 @@ export default class DynamicStringTest {
 }
 
 /**
- * Applies the string factor to all strings.
+ * Applies stringFactor to all strings.
  */
-function applyToStrings( factor: number ): void {
+function applyToAllStrings( stringFactor: number ): void {
   localizedStrings.forEach( localizedString => {
+
+    // Restore the string to its initial value.
     localizedString.restoreInitialValue( 'en' );
 
-    // Strip out all RTL (U+202A), LTR (U+202B), and PDF (U+202C) characters from string.
-    const strippedString = localizedString.property.value.replace( /[\u202A\u202B\u202C]/g, '' );
-    localizedString.property.value = applyToString( strippedString, factor );
+    if ( stringFactor !== 1 ) {
+
+      // Strip out all RTL (U+202A), LTR (U+202B), and PDF (U+202C) characters from string.
+      const strippedString = localizedString.property.value.replace( /[\u202A\u202B\u202C]/g, '' );
+      localizedString.property.value = applyToString( stringFactor, strippedString );
+    }
   } );
 }
 
 /**
- * Applies the string factor to one string.
+ * Applies stringFactor to one string.
  */
-function applyToString( string: string, factor: number ): string {
-  assert && assert( factor > 0, `factor must be > 0: ${factor}` );
+function applyToString( stringFactor: number, string: string ): string {
+  assert && assert( stringFactor > 0, `stringFactor must be > 0: ${stringFactor}` );
 
-  if ( factor > 1 ) {
-    return doubleString( string, factor );
+  if ( stringFactor > 1 ) {
+    return doubleString( string, stringFactor );
   }
   else {
 
-    // Create an array of all placeholders that are present in the string. These are strings surrounded by 2 sets of
-    // curly braces, like '{{value}}'. This will be an empty array if no match is found.
+    // Create an array of all placeholders that are present in the string. Each placeholder is a substrings surrounded
+    // by 2 sets of curly braces, like '{{value}}'. This will be an empty array if no match is found.
     const placeholders = string.match( /{{(.+?)}}/g ) || [];
 
     // Remove all placeholders from the string.
     const noPlaceholdersString = string.replace( /{{(.+?)}}/g, '' );
 
     // Reduce the length of the string.
-    const stringLength = Utils.toFixedNumber( noPlaceholdersString.length * factor + 1, 0 );
+    const stringLength = Utils.toFixedNumber( noPlaceholdersString.length * stringFactor + 1, 0 );
     const reducedString = noPlaceholdersString.substring( 0, stringLength );
 
     // Append placeholders to the end of the reduced string. This will add nothing if placeholders is empty.