diff --git a/.github/workflows/build-and-test.yaml b/.github/workflows/build-and-test.yaml
index c64044a0..ff9ea482 100644
--- a/.github/workflows/build-and-test.yaml
+++ b/.github/workflows/build-and-test.yaml
@@ -7,3 +7,20 @@ jobs:
     with:
       java_version: 21
     secrets: inherit
+
+  javascript-tests:
+    name: JavaScript Tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '18'
+
+      - name: Run JavaScript tests
+        run: |
+          cd webroot/js/test
+          node --test *.test.mjs
diff --git a/webroot/js/component/output.js b/webroot/js/component/output.js
index c7aef5e2..b5c5b257 100644
--- a/webroot/js/component/output.js
+++ b/webroot/js/component/output.js
@@ -15,12 +15,45 @@ function highlightJSON(json) {
     json = JSON.stringify(json, null, 2);
   }
   
+  // Common regex patterns for JSON syntax highlighting
+  
+  // Matches optional whitespace (spaces, tabs, newlines)
+  // Examples: "", " ", "\t", "\n", "  \n  "
+  const optionalWhitespace = '\\s*';
+  
+  // Matches JSON characters that precede a value: colon followed by optional whitespace, or array/object start with optional whitespace
+  // Examples: ": ", ":[", ", ", "[ ", "[42"
+  const valuePrefixes = '(:\\s*|[\\[\\,]\\s*)';
+  
+  // Matches JSON characters that follow a value: comma, closing brackets/braces, newline, or end of string
+  // Examples: ",", "]", "}", "\n", end of string
+  const valueEndings = '(?=\\s*[,\\]\\}\\n]|$)';
+  
+  // Matches quoted strings with escaped characters
+  // Examples: "hello", "world \"quoted\"", "path\\to\\file", "unicode: \\u0041"
+  const quotedString = '"(?:[^"\\\\]|\\\\.)*"';
+  
+  // Matches JSON object keys (quoted strings containing word chars, spaces, underscores, hyphens)
+  // Examples: "name", "user_id", "first-name", "my key", "data_2023"
+  const objectKey = '"[\\w\\s_-]+"';
+  
+  // Matches numbers (integer, decimal, scientific notation)
+  // Examples: 42, -17, 3.14, -0.5, 1e10, 2.5e-3, 1E+5
+  const number = '-?\\d+(?:\\.\\d+)?(?:[eE][+-]?\\d+)?';
+  
+  // Complete regex patterns for each replacement
+  const keyPattern = new RegExp(`(${objectKey})(${optionalWhitespace}:)`, 'g');        // "name": or "user_id" :
+  const stringValuePattern = new RegExp(`(:\\s*)(${quotedString})`, 'g');              // : "John Doe" or :"hello"
+  const numberPattern = new RegExp(`${valuePrefixes}(${number})${valueEndings}`, 'g'); // : 42, [123, or , -3.14
+  const booleanPattern = new RegExp(`${valuePrefixes}(true|false)${valueEndings}`, 'g'); // : true, [false, or , true
+  const nullPattern = new RegExp(`${valuePrefixes}(null)${valueEndings}`, 'g');        // : null, [null, or , null
+  
   return json
-    .replace(/("[\w\s_-]+")(\s*:)/g, '<span class="json-key">$1</span>$2')
-    .replace(/:\s*(".*?")/g, ': <span class="json-string">$1</span>')
-    .replace(/:\s*(\d+\.?\d*)/g, ': <span class="json-number">$1</span>')
-    .replace(/:\s*(true|false)/g, ': <span class="json-boolean">$1</span>')
-    .replace(/:\s*(null)/g, ': <span class="json-null">$1</span>');
+    .replace(keyPattern, '<span class="json-key">$1</span>$2')
+    .replace(stringValuePattern, '$1<span class="json-string">$2</span>')
+    .replace(numberPattern, '$1<span class="json-number">$2</span>')
+    .replace(booleanPattern, '$1<span class="json-boolean">$2</span>')
+    .replace(nullPattern, '$1<span class="json-null">$2</span>');
 }
 
 function formatOutput(data) {
diff --git a/webroot/js/package.json b/webroot/js/package.json
new file mode 100644
index 00000000..3dbc1ca5
--- /dev/null
+++ b/webroot/js/package.json
@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}
diff --git a/webroot/js/test/README.md b/webroot/js/test/README.md
new file mode 100644
index 00000000..495deae9
--- /dev/null
+++ b/webroot/js/test/README.md
@@ -0,0 +1,13 @@
+# JavaScript Unit Tests
+
+This directory contains Node.js unit tests using ES modules and Node.js's built-in `node:test` module.
+
+To run the tests, you need Node.js v18+ installed. Then run:
+
+```bash
+# Run one test file
+node --test webroot/js/test/output.test.mjs
+
+# Run all tests in the directory
+node --test webroot/js/test/
+```
diff --git a/webroot/js/test/output.test.mjs b/webroot/js/test/output.test.mjs
new file mode 100644
index 00000000..a463482c
--- /dev/null
+++ b/webroot/js/test/output.test.mjs
@@ -0,0 +1,160 @@
+import { test, describe } from 'node:test';
+import assert from 'node:assert';
+import { highlightJSON } from '../component/output.js';
+
+describe('highlightJSON', () => {
+  test('should highlight numbers', () => {
+    const input = { count: 42 };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"count"</span>:<span class="json-number">42</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should not highlight numbers within strings', () => {
+    const input = { 
+      link_id: "aws:us-west-2:94889860-0a55-4fbd-981e-3a9ce99ca1ec" 
+    };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"link_id"</span>:<span class="json-string">"aws:us-west-2:94889860-0a55-4fbd-981e-3a9ce99ca1ec"</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle mixed numbers and strings', () => {
+    const input = {
+      service_id: 8,
+      site_id: 276,
+      link_id: "aws:us-west-2:94889860-0a55-4fbd-981e-3a9ce99ca1ec"
+    };
+    const result = highlightJSON(JSON.stringify(input, null, 2));
+    
+    const expected = `{
+  <span class="json-key">"service_id"</span>: <span class="json-number">8</span>,
+  <span class="json-key">"site_id"</span>: <span class="json-number">276</span>,
+  <span class="json-key">"link_id"</span>: <span class="json-string">"aws:us-west-2:94889860-0a55-4fbd-981e-3a9ce99ca1ec"</span>
+}`;
+    assert.strictEqual(result, expected);
+  });
+
+  test('should highlight strings', () => {
+    const input = { name: "test-value" };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"name"</span>:<span class="json-string">"test-value"</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should highlight keys', () => {
+    const input = { test_key: "value" };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"test_key"</span>:<span class="json-string">"value"</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should highlight booleans', () => {
+    const input = { flag: true, disabled: false };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"flag"</span>:<span class="json-boolean">true</span>,<span class="json-key">"disabled"</span>:<span class="json-boolean">false</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should highlight null', () => {
+    const input = { value: null };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"value"</span>:<span class="json-null">null</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle negative numbers', () => {
+    const input = { temperature: -15 };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"temperature"</span>:<span class="json-number">-15</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle decimal numbers', () => {
+    const input = { price: 19.99 };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"price"</span>:<span class="json-number">19.99</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle scientific notation', () => {
+    const input = { value: 1.23e-4 };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"value"</span>:<span class="json-number">0.000123</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle nested objects', () => {
+    const input = {
+      user: {
+        id: 123,
+        name: "John Doe",
+        active: true,
+        metadata: null,
+        scores: [95.5, -2.3, 0]
+      }
+    };
+    const result = highlightJSON(JSON.stringify(input, null, 2));
+    
+    const expected = `{
+  <span class="json-key">"user"</span>: {
+    <span class="json-key">"id"</span>: <span class="json-number">123</span>,
+    <span class="json-key">"name"</span>: <span class="json-string">"John Doe"</span>,
+    <span class="json-key">"active"</span>: <span class="json-boolean">true</span>,
+    <span class="json-key">"metadata"</span>: <span class="json-null">null</span>,
+    <span class="json-key">"scores"</span>: [
+      <span class="json-number">95.5</span>,
+      <span class="json-number">-2.3</span>,
+      <span class="json-number">0</span>
+    ]
+  }
+}`;
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle escaped quotes', () => {
+    const input = { 
+      message: 'He said "Hello, world!" to everyone' 
+    };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"message"</span>:<span class="json-string">"He said \\"Hello, world!\\" to everyone"</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle empty objects and arrays', () => {
+    const input = { empty_obj: {}, empty_array: [] };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"empty_obj"</span>:{},<span class="json-key">"empty_array"</span>:[]}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle special characters in strings', () => {
+    const input = { 
+      special: "Line 1\nLine 2\tTabbed\r\nWindows line ending",
+      unicode: "Unicode: 🚀 ñ é"
+    };
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '{<span class="json-key">"special"</span>:<span class="json-string">"Line 1\\nLine 2\\tTabbed\\r\\nWindows line ending"</span>,<span class="json-key">"unicode"</span>:<span class="json-string">"Unicode: 🚀 ñ é"</span>}';
+    assert.strictEqual(result, expected);
+  });
+
+  test('should handle non-object input', () => {
+    const input = [1, 2, 3];
+    const result = highlightJSON(JSON.stringify(input));
+    
+    const expected = '[<span class="json-number">1</span>,<span class="json-number">2</span>,<span class="json-number">3</span>]';
+    assert.strictEqual(result, expected);
+  });
+});