JavaScript Highlighter: Fix potential infinite loop on bad input

while typing

MongoView/Synax Highlighting/JavaScriptHighlighter.swift

@@ -225,8 +225,6 @@ class JavaScriptHighlighter {
             consumeDotLookup()
         } else if char == "?" {
             consumeTernaryExpression()
-        } else if expressionEnds.contains(char) {
-            return
         } else {
             consume()
         }

MongoView/Views/JavaScriptEditorView.swift

@@ -7,12 +7,13 @@
 //
 
 import AppKit
+import Combine
 
 class JavaScriptEditorView: NSTextView {
     
     var highlighter = JavaScriptHighlighter()
     private var isRehighlighting = false
-    
+
     override var string: String {
         get {
             super.string
@@ -23,6 +24,9 @@ class JavaScriptEditorView: NSTextView {
             rehighlight()
         }
     }
+    
+    private let rehighlightSubject = PassthroughSubject<Void, Never>()
+    private var debouncedRehighlightCancellable: AnyCancellable!
 
     func rehighlight() {
         isRehighlighting = true
@@ -34,6 +38,13 @@ class JavaScriptEditorView: NSTextView {
         super.awakeFromNib()
         
         textStorage!.delegate = self
+        
+        typingAttributes = [
+            .font: NSFont.monospacedSystemFont(ofSize: 13, weight: .regular),
+            .foregroundColor: NSColor.textColor
+        ]
+        
+        debouncedRehighlightCancellable = rehighlightSubject.throttle(for: .milliseconds(40), scheduler: RunLoop.main, latest: false).sink(receiveValue: rehighlight)
     }
     
     override func shouldChangeText(in affectedCharRange: NSRange, replacementString: String?) -> Bool {
@@ -117,6 +128,6 @@ extension JavaScriptEditorView: NSTextStorageDelegate {
             }
         }
         
-        rehighlight()
+        rehighlightSubject.send()
     }
 }