add deep merge

tests/cypress/integration/core/mergeDeep.spec.ts

@@ -0,0 +1,68 @@
+/// <reference types="cypress" />
+
+import mergeDeep from '@tiptap/core/src/utilities/mergeDeep'
+
+describe('mergeDeep', () => {
+  it('should merge', () => {
+    const one = {
+      a: 1,
+    }
+    const two = {
+      b: 1,
+    }
+    const result = {
+      a: 1,
+      b: 1,
+    }
+    const merged = mergeDeep(one, two)
+
+    expect(merged).to.deep.eq(result)
+  })
+
+  it('should not merge array', () => {
+    const one = {
+      a: [1],
+    }
+    const two = {
+      a: [2],
+    }
+    const result = {
+      a: [2],
+    }
+    const merged = mergeDeep(one, two)
+
+    expect(merged).to.deep.eq(result)
+  })
+
+  it('should merge deep', () => {
+    const one = {
+      a: 1,
+      b: {
+        c: true,
+      },
+      d: {
+        e: true,
+        f: [1],
+      },
+    }
+    const two = {
+      b: 1,
+      d: {
+        f: [2],
+        g: 1,
+      },
+    }
+    const result = {
+      a: 1,
+      b: 1,
+      d: {
+        e: true,
+        f: [2],
+        g: 1,
+      },
+    }
+    const merged = mergeDeep(one, two)
+
+    expect(merged).to.deep.eq(result)
+  })
+})