diff --git a/js/tests/unit/tooltip.spec.js b/js/tests/unit/tooltip.spec.js
index 3e5c9179401b..611fadfe1c5b 100644
--- a/js/tests/unit/tooltip.spec.js
+++ b/js/tests/unit/tooltip.spec.js
@@ -317,7 +317,7 @@ describe('Tooltip', () => {
 
         expect(tooltipShown).toBeDefined()
         expect(tooltipEl.getAttribute('aria-describedby')).toEqual(tooltipShown.getAttribute('id'))
-        expect(tooltipShown.getAttribute('id').indexOf('tooltip') !== -1).toEqual(true)
+        expect(tooltipShown.getAttribute('id')).toContain('tooltip')
         done()
       })
 
diff --git a/js/tests/unit/util/sanitizer.spec.js b/js/tests/unit/util/sanitizer.spec.js
index dcfad8436f8f..395875d62402 100644
--- a/js/tests/unit/util/sanitizer.spec.js
+++ b/js/tests/unit/util/sanitizer.spec.js
@@ -20,7 +20,7 @@ describe('Sanitizer', () => {
 
       const result = sanitizeHtml(template, DefaultAllowlist, null)
 
-      expect(result.indexOf('script') === -1).toEqual(true)
+      expect(result).not.toContain('script')
     })
 
     it('should allow aria attributes and safe attributes', () => {
@@ -32,8 +32,8 @@ describe('Sanitizer', () => {
 
       const result = sanitizeHtml(template, DefaultAllowlist, null)
 
-      expect(result.indexOf('aria-pressed') !== -1).toEqual(true)
-      expect(result.indexOf('class="test"') !== -1).toEqual(true)
+      expect(result).toContain('aria-pressed')
+      expect(result).toContain('class="test"')
     })
 
     it('should remove tags not in allowlist', () => {
@@ -45,7 +45,7 @@ describe('Sanitizer', () => {
 
       const result = sanitizeHtml(template, DefaultAllowlist, null)
 
-      expect(result.indexOf('<script>') === -1).toEqual(true)
+      expect(result).not.toContain('<script>')
     })
 
     it('should not use native api to sanitize if a custom function passed', () => {