Add getOrCreateInstance method in base-component (#33276)

Co-authored-by: Rohit Sharma <rohit2sharma95@gmail.com>
Co-authored-by: XhmikosR <xhmikosr@gmail.com>

js/tests/unit/toast.spec.js

@@ -591,4 +591,58 @@ describe('Toast', () => {
       expect(Toast.getInstance(div)).toEqual(null)
     })
   })
+
+  describe('getOrCreateInstance', () => {
+    it('should return toast instance', () => {
+      fixtureEl.innerHTML = '<div></div>'
+
+      const div = fixtureEl.querySelector('div')
+      const toast = new Toast(div)
+
+      expect(Toast.getOrCreateInstance(div)).toEqual(toast)
+      expect(Toast.getInstance(div)).toEqual(Toast.getOrCreateInstance(div, {}))
+      expect(Toast.getOrCreateInstance(div)).toBeInstanceOf(Toast)
+    })
+
+    it('should return new instance when there is no toast instance', () => {
+      fixtureEl.innerHTML = '<div></div>'
+
+      const div = fixtureEl.querySelector('div')
+
+      expect(Toast.getInstance(div)).toEqual(null)
+      expect(Toast.getOrCreateInstance(div)).toBeInstanceOf(Toast)
+    })
+
+    it('should return new instance when there is no toast instance with given configuration', () => {
+      fixtureEl.innerHTML = '<div></div>'
+
+      const div = fixtureEl.querySelector('div')
+
+      expect(Toast.getInstance(div)).toEqual(null)
+      const toast = Toast.getOrCreateInstance(div, {
+        delay: 1
+      })
+      expect(toast).toBeInstanceOf(Toast)
+
+      expect(toast._config.delay).toEqual(1)
+    })
+
+    it('should return the instance when exists without given configuration', () => {
+      fixtureEl.innerHTML = '<div></div>'
+
+      const div = fixtureEl.querySelector('div')
+      const toast = new Toast(div, {
+        delay: 1
+      })
+      expect(Toast.getInstance(div)).toEqual(toast)
+
+      const toast2 = Toast.getOrCreateInstance(div, {
+        delay: 2
+      })
+      expect(toast).toBeInstanceOf(Toast)
+      expect(toast2).toEqual(toast)
+
+      expect(toast2._config.delay).toEqual(1)
+    })
+  })
 })