docs: usingMatchers mention toStrictEqual (#13560)

Author: necipallef

CHANGELOG.md

@@ -13,6 +13,7 @@
 ### Chore & Maintenance
 
 - `[@jest/transform]` Update `convert-source-map` ([#13509](https://github.com/facebook/jest/pull/13509))
+- `[docs]` Mention `toStrictEqual` in UsingMatchers docs. ([#13560](https://github.com/facebook/jest/pull/13560))
 
 ### Performance
 

docs/UsingMatchers.md

@@ -17,7 +17,7 @@ test('two plus two is four', () => {
 
 In this code, `expect(2 + 2)` returns an "expectation" object. You typically won't do much with these expectation objects except call matchers on them. In this code, `.toBe(4)` is the matcher. When Jest runs, it tracks all the failing matchers so that it can print out nice error messages for you.
 
-`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` instead:
+`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` or `toStrictEqual` instead:
 
 ```js
 test('object assignment', () => {
@@ -29,7 +29,13 @@ test('object assignment', () => {
 
 `toEqual` recursively checks every field of an object or array.
 
-You can also test for the opposite of a matcher:
+:::tip
+
+Using `toStrictEqual` is preferred over using `toEqual`. `toEqual` simply ignores `undefined` values, whereas `toStrictEqual` takes them into account.
+
+:::
+
+You can also test for the opposite of a matcher using `not`:
 
 ```js
 test('adding positive numbers is not zero', () => {

website/versioned_docs/version-25.x/UsingMatchers.md

@@ -17,7 +17,7 @@ test('two plus two is four', () => {
 
 In this code, `expect(2 + 2)` returns an "expectation" object. You typically won't do much with these expectation objects except call matchers on them. In this code, `.toBe(4)` is the matcher. When Jest runs, it tracks all the failing matchers so that it can print out nice error messages for you.
 
-`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` instead:
+`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` or `toStrictEqual` instead:
 
 ```js
 test('object assignment', () => {
@@ -29,7 +29,13 @@ test('object assignment', () => {
 
 `toEqual` recursively checks every field of an object or array.
 
-You can also test for the opposite of a matcher:
+:::tip
+
+Using `toStrictEqual` is preferred over using `toEqual`. `toEqual` simply ignores `undefined` values, whereas `toStrictEqual` takes them into account.
+
+:::
+
+You can also test for the opposite of a matcher using `not`:
 
 ```js
 test('adding positive numbers is not zero', () => {

website/versioned_docs/version-26.x/UsingMatchers.md

@@ -17,7 +17,7 @@ test('two plus two is four', () => {
 
 In this code, `expect(2 + 2)` returns an "expectation" object. You typically won't do much with these expectation objects except call matchers on them. In this code, `.toBe(4)` is the matcher. When Jest runs, it tracks all the failing matchers so that it can print out nice error messages for you.
 
-`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` instead:
+`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` or `toStrictEqual` instead:
 
 ```js
 test('object assignment', () => {
@@ -29,7 +29,13 @@ test('object assignment', () => {
 
 `toEqual` recursively checks every field of an object or array.
 
-You can also test for the opposite of a matcher:
+:::tip
+
+Using `toStrictEqual` is preferred over using `toEqual`. `toEqual` simply ignores `undefined` values, whereas `toStrictEqual` takes them into account.
+
+:::
+
+You can also test for the opposite of a matcher using `not`:
 
 ```js
 test('adding positive numbers is not zero', () => {

website/versioned_docs/version-27.x/UsingMatchers.md

@@ -17,7 +17,7 @@ test('two plus two is four', () => {
 
 In this code, `expect(2 + 2)` returns an "expectation" object. You typically won't do much with these expectation objects except call matchers on them. In this code, `.toBe(4)` is the matcher. When Jest runs, it tracks all the failing matchers so that it can print out nice error messages for you.
 
-`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` instead:
+`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` or `toStrictEqual` instead:
 
 ```js
 test('object assignment', () => {
@@ -29,7 +29,13 @@ test('object assignment', () => {
 
 `toEqual` recursively checks every field of an object or array.
 
-You can also test for the opposite of a matcher:
+:::tip
+
+Using `toStrictEqual` is preferred over using `toEqual`. `toEqual` simply ignores `undefined` values, whereas `toStrictEqual` takes them into account.
+
+:::
+
+You can also test for the opposite of a matcher using `not`:
 
 ```js
 test('adding positive numbers is not zero', () => {

website/versioned_docs/version-28.x/UsingMatchers.md

@@ -17,7 +17,7 @@ test('two plus two is four', () => {
 
 In this code, `expect(2 + 2)` returns an "expectation" object. You typically won't do much with these expectation objects except call matchers on them. In this code, `.toBe(4)` is the matcher. When Jest runs, it tracks all the failing matchers so that it can print out nice error messages for you.
 
-`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` instead:
+`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` or `toStrictEqual` instead:
 
 ```js
 test('object assignment', () => {
@@ -29,7 +29,13 @@ test('object assignment', () => {
 
 `toEqual` recursively checks every field of an object or array.
 
-You can also test for the opposite of a matcher:
+:::tip
+
+Using `toStrictEqual` is preferred over using `toEqual`. `toEqual` simply ignores `undefined` values, whereas `toStrictEqual` takes them into account.
+
+:::
+
+You can also test for the opposite of a matcher using `not`:
 
 ```js
 test('adding positive numbers is not zero', () => {

website/versioned_docs/version-29.0/UsingMatchers.md

@@ -17,7 +17,7 @@ test('two plus two is four', () => {
 
 In this code, `expect(2 + 2)` returns an "expectation" object. You typically won't do much with these expectation objects except call matchers on them. In this code, `.toBe(4)` is the matcher. When Jest runs, it tracks all the failing matchers so that it can print out nice error messages for you.
 
-`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` instead:
+`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` or `toStrictEqual` instead:
 
 ```js
 test('object assignment', () => {
@@ -29,7 +29,13 @@ test('object assignment', () => {
 
 `toEqual` recursively checks every field of an object or array.
 
-You can also test for the opposite of a matcher:
+:::tip
+
+Using `toStrictEqual` is preferred over using `toEqual`. `toEqual` simply ignores `undefined` values, whereas `toStrictEqual` takes them into account.
+
+:::
+
+You can also test for the opposite of a matcher using `not`:
 
 ```js
 test('adding positive numbers is not zero', () => {

website/versioned_docs/version-29.1/UsingMatchers.md

@@ -17,7 +17,7 @@ test('two plus two is four', () => {
 
 In this code, `expect(2 + 2)` returns an "expectation" object. You typically won't do much with these expectation objects except call matchers on them. In this code, `.toBe(4)` is the matcher. When Jest runs, it tracks all the failing matchers so that it can print out nice error messages for you.
 
-`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` instead:
+`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` or `toStrictEqual` instead:
 
 ```js
 test('object assignment', () => {
@@ -29,7 +29,13 @@ test('object assignment', () => {
 
 `toEqual` recursively checks every field of an object or array.
 
-You can also test for the opposite of a matcher:
+:::tip
+
+Using `toStrictEqual` is preferred over using `toEqual`. `toEqual` simply ignores `undefined` values, whereas `toStrictEqual` takes them into account.
+
+:::
+
+You can also test for the opposite of a matcher using `not`:
 
 ```js
 test('adding positive numbers is not zero', () => {

website/versioned_docs/version-29.2/UsingMatchers.md

@@ -17,7 +17,7 @@ test('two plus two is four', () => {
 
 In this code, `expect(2 + 2)` returns an "expectation" object. You typically won't do much with these expectation objects except call matchers on them. In this code, `.toBe(4)` is the matcher. When Jest runs, it tracks all the failing matchers so that it can print out nice error messages for you.
 
-`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` instead:
+`toBe` uses `Object.is` to test exact equality. If you want to check the value of an object, use `toEqual` or `toStrictEqual` instead:
 
 ```js
 test('object assignment', () => {
@@ -29,7 +29,13 @@ test('object assignment', () => {
 
 `toEqual` recursively checks every field of an object or array.
 
-You can also test for the opposite of a matcher:
+:::tip
+
+Using `toStrictEqual` is preferred over using `toEqual`. `toEqual` simply ignores `undefined` values, whereas `toStrictEqual` takes them into account.
+
+:::
+
+You can also test for the opposite of a matcher using `not`:
 
 ```js
 test('adding positive numbers is not zero', () => {