From e7a1496fcbcfc11028d885ae50488e577009548d Mon Sep 17 00:00:00 2001
From: jahorton <jahorton@sil.org>
Date: Mon, 23 Mar 2020 11:16:20 +0700
Subject: [PATCH] refactor(web/engine): more PR review addressing

---
 web/source/text/defaultOutput.ts | 17 +++++++++++++----
 web/source/text/processor.ts     | 14 ++++++++------
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/web/source/text/defaultOutput.ts b/web/source/text/defaultOutput.ts
index 77b9d12150..7f5bf3d157 100644
--- a/web/source/text/defaultOutput.ts
+++ b/web/source/text/defaultOutput.ts
@@ -4,6 +4,12 @@
 /// <reference path="keyEvent.ts" />
 
 namespace com.keyman.text {
+  export enum EmulationKeystrokes {
+    Space = ' ',
+    Enter = '\n',
+    Backspace = '\b'
+  }
+
   /**
    * Defines a collection of static library functions that define KeymanWeb's default (implied) keyboard rule behaviors.
    */
@@ -141,18 +147,21 @@ namespace com.keyman.text {
      * Codes matched here generally have default implementations when in a browser but require emulation
      * for 'synthetic' `OutputTarget`s like `Mock`s, which have no default text handling.
      */
-    public static forSpecialEmulation(Lkc: KeyEvent): string {
+    public static forSpecialEmulation(Lkc: KeyEvent): EmulationKeystrokes {
       let code = DefaultOutput.codeForEvent(Lkc);
 
       switch(code) {
         case Codes.keyCodes['K_BKSP']:
-          return '\b';
+          return EmulationKeystrokes.Backspace;
         case Codes.keyCodes['K_ENTER']:
-          return '\n'; 
+          return EmulationKeystrokes.Enter;
+        // (Probably) only here for legacy reasons; it's always been handled alongside the other two.
         case Codes.keyCodes['K_SPACE']:
-          return ' ';
+          return EmulationKeystrokes.Space;
         // case Codes.keyCodes['K_DEL']:
         //   return '\u007f'; // 127, ASCII / Unicode control code for DEL.
+        default:
+          return null;
       }
     }
 
diff --git a/web/source/text/processor.ts b/web/source/text/processor.ts
index 42f071b106..2e5222c8af 100644
--- a/web/source/text/processor.ts
+++ b/web/source/text/processor.ts
@@ -53,6 +53,7 @@ namespace com.keyman.text {
 
       let matched = false;
       var char = '';
+      var special: EmulationKeystrokes;
       if(usingOSK || outputTarget.isSynthetic) {
         matched = true;  // All the conditions below result in matches until the final else, which restores the expected default
                          // if no match occurs.
@@ -63,22 +64,23 @@ namespace com.keyman.text {
 
           // We'd rather let the browser handle these keys, but we're using emulated keystrokes, forcing KMW
           // to emulate default behavior here.
-        } else if(char = DefaultOutput.forSpecialEmulation(Lkc)) { 
-          switch(char) {
-            case '\b':
+        } else if(special = DefaultOutput.forSpecialEmulation(Lkc)) { 
+          switch(special) {
+            case EmulationKeystrokes.Backspace:
               keyman.interface.defaultBackspace(outputTarget);
               break;
-            case '\n':
+            case EmulationKeystrokes.Enter:
               outputTarget.handleNewlineAtCaret();
               break;
-            case ' ':
+            case EmulationKeystrokes.Space:
               keyman.interface.output(0, outputTarget, ' ');
               break;
             // case '\u007f': // K_DEL
               // // For (possible) future implementation.
               // // Would recommend (conceptually) equaling K_RIGHT + K_BKSP, the former of which would technically be a 'command'.
             default:
-              ruleBehavior.errorLog = "Unexpected 'special emulation' character (\\u" + char.kmwCharCodeAt(0).toString(16) + ") went unhandled!";
+              // In case we extend the allowed set, but forget to implement its handling case above.
+              ruleBehavior.errorLog = "Unexpected 'special emulation' character (\\u" + (special as String).kmwCharCodeAt(0).toString(16) + ") went unhandled!";
           } 
         } else {
           // Back to the standard default, pending normal matching.