Merge branch 'add_toBeNullish' of https://github.com/MattMcCherry/jasmine

* Merges #2045 from @MattMcCherry

spec/core/integration/MatchersSpec.js

@@ -469,6 +469,24 @@ describe('Matchers (Integration)', function() {
     });
   });
 
+  describe('toBeNullish', function() {
+    verifyPasses(function(env) {
+      env.expect(undefined).toBeNullish();
+    });
+
+    verifyPasses(function(env) {
+      env.expect(null).toBeNullish();
+    });
+
+    verifyFails(function(env) {
+      env.expect(1).toBeNullish();
+    });
+
+    verifyFails(function(env) {
+      env.expect('').toBeNullish();
+    });
+  });
+
   describe('toContain', function() {
     verifyPasses(function(env) {
       env.addCustomEqualityTester(function(a, b) {

spec/core/matchers/toBeNullishSpec.js

@@ -0,0 +1,57 @@
+describe('toBeNullish', function() {
+  it('passes for null values', function() {
+    const matcher = jasmineUnderTest.matchers.toBeNullish();
+    const result = matcher.compare(null);
+    expect(result.pass).toBe(true);
+  });
+
+  it('passes for undefined values', function() {
+    const matcher = jasmineUnderTest.matchers.toBeNullish();
+    const result = matcher.compare(void 0);
+    expect(result.pass).toBe(true);
+  });
+
+  it('fails when matching defined values', function() {
+    const matcher = jasmineUnderTest.matchers.toBeNullish();
+    const result = matcher.compare('foo');
+    expect(result.pass).toBe(false);
+  });
+
+  describe('falsy values', () => {
+    it('fails for 0', function() {
+      const matcher = jasmineUnderTest.matchers.toBeNullish();
+      const result = matcher.compare(0);
+      expect(result.pass).toBe(false);
+    });
+
+    it('fails for -0', function() {
+      const matcher = jasmineUnderTest.matchers.toBeNullish();
+      const result = matcher.compare(-0);
+      expect(result.pass).toBe(false);
+    });
+
+    it('fails for empty string', function() {
+      const matcher = jasmineUnderTest.matchers.toBeNullish();
+      const result = matcher.compare('');
+      expect(result.pass).toBe(false);
+    });
+
+    it('fails for false', function() {
+      const matcher = jasmineUnderTest.matchers.toBeNullish();
+      const result = matcher.compare(false);
+      expect(result.pass).toBe(false);
+    });
+
+    it('fails for NaN', function() {
+      const matcher = jasmineUnderTest.matchers.toBeNullish();
+      const result = matcher.compare(NaN);
+      expect(result.pass).toBe(false);
+    });
+
+    it('fails for 0n', function() {
+      const matcher = jasmineUnderTest.matchers.toBeNullish();
+      const result = matcher.compare(BigInt(0));
+      expect(result.pass).toBe(false);
+    });
+  });
+});