Add isEqual and isNotEqual utility

common/changes/@uifabric/utilities/feature-isEqual-function_2018-04-18-21-10.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "@uifabric/utilities",
+      "comment": "Add isEqual and isNotEqual utilities",
+      "type": "patch"
+    }
+  ],
+  "packageName": "@uifabric/utilities",
+  "email": "v-jojanz@microsoft.com"
+}

common/changes/office-ui-fabric-react/feature-isEqual-function_2018-04-18-21-10.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "office-ui-fabric-react",
+      "comment": "Fix #3607",
+      "type": "patch"
+    }
+  ],
+  "packageName": "office-ui-fabric-react",
+  "email": "v-jojanz@microsoft.com"
+}

packages/office-ui-fabric-react/src/components/List/List.tsx

@@ -9,7 +9,8 @@ import {
   divProperties,
   getNativeProps,
   IRenderFunction,
-  createRef
+  createRef,
+  isEqual,
 } from '../../Utilities';
 import { IList, IListProps, IPage, IPageProps } from './List.types';
 
@@ -299,7 +300,7 @@ export class List extends BaseComponent<IListProps, IListState> implements IList
       return true;
     }
 
-    if (newProps.items === this.props.items &&
+    if (isEqual(newProps.items, this.props.items) &&
       oldPages!.length === newPages!.length) {
       for (let i = 0; i < oldPages!.length; i++) {
         const oldPage = oldPages![i];

packages/utilities/src/index.ts

@@ -41,4 +41,5 @@ export * from './scroll';
 export * from './string';
 export * from './styled';
 export * from './warn';
-export * from './createRef';
+export * from './createRef';
+export * from './isEqual';

packages/utilities/src/isEqual.test.ts

@@ -0,0 +1,125 @@
+import { isEqual, isNotEqual } from './isEqual';
+
+describe('isEquals and isNotEquals function helper', () => {
+  describe('Test indexes', () => {
+    // Set up arrays to compare
+    const arrayBase = ['1', '2', '3'];
+    const arrayControl = ['1', '2', '3'];
+    const arrayDifferentValues = ['1', '2', '4'];
+    const arrayDifferentTypes = ['1', '2', 3];
+    const arrayDifferentLength = ['1', '2', '3', '4'];
+
+    describe('isEqual', () => {
+      it('returns true with arrays with the same values', () => {
+        expect(isEqual(arrayBase, arrayControl)).toEqual(true);
+      });
+
+      it('returns false with arrays with different values', () => {
+        expect(isEqual(arrayBase, arrayDifferentValues)).toEqual(false);
+      });
+
+      it('returns false with arrays with different types', () => {
+        expect(isEqual(arrayBase, arrayDifferentTypes)).toEqual(false);
+      });
+
+      it('returns false with arrays with different length', () => {
+        expect(isEqual(arrayBase, arrayDifferentLength)).toEqual(false);
+      });
+    });
+
+    describe('isNotEqual', () => {
+      it('returns true with arrays with the same values', () => {
+        expect(isNotEqual(arrayBase, arrayControl)).toEqual(false);
+      });
+    });
+  });
+
+  describe('Test objects', () => {
+    // Set up objects to compare
+    const objectBase = { a: '1', b: '2' };
+    const objectControl = { a: '1', b: '2' };
+    const objectDifferentValues = { a: '1', b: '3' };
+    const objectDifferentValueTypes = { a: '1', b: 2 };
+    const objectDifferentKeyTypes = { 1: '1', 2: '2' };
+    const objectDifferentLength = { a: '1', b: '2', c: '3' };
+
+    describe('isEqual', () => {
+      it('returns true with objects with the same values', () => {
+        expect(isEqual(objectBase, objectControl)).toEqual(true);
+      });
+
+      it('returns false with objects with different values', () => {
+        expect(isEqual(objectBase, objectDifferentValues)).toEqual(false);
+      });
+
+      it('returns false with objects with different value types', () => {
+        expect(isEqual(objectBase, objectDifferentValueTypes)).toEqual(false);
+      });
+
+      it('returns false with objects with different key types', () => {
+        expect(isEqual(objectBase, objectDifferentKeyTypes)).toEqual(false);
+      });
+
+      it('returns false with objects with different length', () => {
+        expect(isEqual(objectBase, objectDifferentLength)).toEqual(false);
+      });
+    });
+
+    describe('isNotEqual', () => {
+      it('returns true with objects with the same values', () => {
+        expect(isNotEqual(objectBase, objectControl)).toEqual(false);
+      });
+    });
+  });
+
+  describe('Test numbers', () => {
+    // Set up numbers to compare
+    const numberBase = 123;
+    const numberControl = 123;
+    const numberDifferentValues = 1234;
+    const numberDifferentTypes = '123';
+
+    describe('isEqual', () => {
+      it('returns true with numbers with the same values', () => {
+        expect(isEqual(numberBase, numberControl)).toEqual(true);
+      });
+
+      it('returns false with numbers with different values', () => {
+        expect(isEqual(numberBase, numberDifferentValues)).toEqual(false);
+      });
+
+      it('returns false with numbers with different types', () => {
+        expect(isEqual(numberBase, numberDifferentTypes)).toEqual(false);
+      });
+    });
+
+    describe('isNotEqual', () => {
+      it('returns true with numbers with the same values', () => {
+        expect(isNotEqual(numberBase, numberControl)).toEqual(false);
+      });
+    });
+  });
+
+  describe('Test strings', () => {
+    // Set up strings to compare
+    const stringBase = 'This is a string';
+    const stringControl = 'This is a string';
+    const stringDifferentValues = 'This is a string that isn\'t the same';
+
+    describe('isEqual', () => {
+      it('returns true with strings with the same values', () => {
+        expect(isEqual(stringBase, stringControl)).toEqual(true);
+      });
+
+      it('returns false with strings with different values', () => {
+        expect(isEqual(stringBase, stringDifferentValues)).toEqual(false);
+      });
+    });
+
+    describe('isNotEqual', () => {
+      it('returns true with strings with the same values', () => {
+        expect(isNotEqual(stringBase, stringControl)).toEqual(false);
+      });
+    });
+  });
+});

packages/utilities/src/isEqual.ts

@@ -0,0 +1,85 @@
+/**
+ * Checks if the first and second items are the NOT same recursively. Use for checking arrays and objects.
+ * @param itemA First item to compare to second item
+ * @param itemB Second item to compare to first item
+ */
+export const isEqual = (itemA: any, itemB: any): boolean => { // tslint:disable-line no-any
+  if (itemA === itemB) {
+    return true;
+  }
+  // Get the value type
+  const type = Object.prototype.toString.call(itemA);
+  // If the two objects are not the same type, return false
+  if (type !== Object.prototype.toString.call(itemB)) {
+    return false;
+  }
+  // If items are not an object or array, return false
+  if (['[object Array]', '[object Object]'].indexOf(type) < 0) {
+    return false;
+  }
+  // Compare the length of the length of the two items
+  const valueLen = type === '[object Array]' ? itemA.length : Object.keys(itemA).length;
+  const otherLen = type === '[object Array]' ? itemB.length : Object.keys(itemB).length;
+  if (valueLen !== otherLen) {
+    return false;
+  }
+  // Compare two items
+  const compare = (item1: any, item2: any) => {  // tslint:disable-line no-any
+
+    // Get the object type
+    const itemType = Object.prototype.toString.call(item1);
+
+    // If an object or array, compare recursively
+    if (['[object Array]', '[object Object]'].indexOf(itemType) >= 0) {
+      if (!isEqual(item1, item2)) {
+        return false;
+      }
+    } else {
+
+      // If the two items are not the same type, return false
+      if (itemType !== Object.prototype.toString.call(item2)) {
+        return false;
+      }
+
+      // Else if it's a function, convert to a string and compare
+      // Otherwise, just compare
+      if (itemType === '[object Function]') {
+        if (item1.toString() !== item2.toString()) {
+          return false;
+        }
+      } else {
+        if (item1 !== item2) {
+          return false;
+        }
+      }
+
+    }
+  };
+  // Compare properties
+  if (type === '[object Array]') {
+    for (let i = 0; i < valueLen; i++) {
+      if (compare(itemA[i], itemB[i]) === false) {
+        return false;
+      }
+    }
+  } else {
+    for (const key in itemA) {
+      if (itemA.hasOwnProperty(key)) {
+        if (compare(itemA[key], itemB[key]) === false) {
+          return false;
+        }
+      }
+    }
+  }
+  // If nothing failed, return true
+  return true;
+};
+
+/**
+ * Checks if the first and second items are the NOT same recursively. Use for checking arrays and objects.
+ * @param itemA First item to compare to second item
+ * @param itemB Second item to compare to first item
+ */
+export const isNotEqual = (itemA: any, itemB: any): boolean => { // tslint:disable-line no-any
+  return !isEqual(itemA, itemB);
+};