From b5b7367c907126dcef33fb24e50c1a7b3253ed8f Mon Sep 17 00:00:00 2001
From: "M.K. Safi" <msafi@msafi.com>
Date: Sat, 16 Mar 2019 16:59:11 -0700
Subject: [PATCH 1/2] Add support for bigint to pretty-format

---
 .../src/__tests__/prettyFormat.test.ts        | 20 +++++++++++++++++++
 packages/pretty-format/src/index.ts           |  7 +++++++
 2 files changed, 27 insertions(+)

diff --git a/packages/pretty-format/src/__tests__/prettyFormat.test.ts b/packages/pretty-format/src/__tests__/prettyFormat.test.ts
index bcfca99f7c3d..8365d3df7d94 100644
--- a/packages/pretty-format/src/__tests__/prettyFormat.test.ts
+++ b/packages/pretty-format/src/__tests__/prettyFormat.test.ts
@@ -209,21 +209,41 @@ describe('prettyFormat()', () => {
     expect(prettyFormat(val)).toEqual('123');
   });
 
+  it('prints a positive bigint', () => {
+    const val = BigInt(123);
+    expect(prettyFormat(val)).toEqual('123n');
+  });
+
   it('prints a negative number', () => {
     const val = -123;
     expect(prettyFormat(val)).toEqual('-123');
   });
 
+  it('prints a negative bigint', () => {
+    const val = BigInt(-123);
+    expect(prettyFormat(val)).toEqual('-123n');
+  });
+
   it('prints zero', () => {
     const val = 0;
     expect(prettyFormat(val)).toEqual('0');
   });
 
+  it('prints zero bigint', () => {
+    const val = BigInt(0);
+    expect(prettyFormat(val)).toEqual('0n');
+  });
+
   it('prints negative zero', () => {
     const val = -0;
     expect(prettyFormat(val)).toEqual('-0');
   });
 
+  it('prints negative zero bigint', () => {
+    const val = BigInt(-0);
+    expect(prettyFormat(val)).toEqual('0n');
+  });
+
   it('prints a date', () => {
     const val = new Date(10e11);
     expect(prettyFormat(val)).toEqual('2001-09-09T01:46:40.000Z');
diff --git a/packages/pretty-format/src/index.ts b/packages/pretty-format/src/index.ts
index b4daddc17114..aafe7cfc08d4 100644
--- a/packages/pretty-format/src/index.ts
+++ b/packages/pretty-format/src/index.ts
@@ -72,6 +72,10 @@ function printNumber(val: number): string {
   return Object.is(val, -0) ? '-0' : String(val);
 }
 
+function printBigInt(val: bigint): string {
+  return String(`${val}n`);
+}
+
 function printFunction(val: Function, printFunctionName: boolean): string {
   if (!printFunctionName) {
     return '[Function]';
@@ -112,6 +116,9 @@ function printBasicValue(
   if (typeOf === 'number') {
     return printNumber(val);
   }
+  if (typeOf === 'bigint') {
+    return printBigInt(val);
+  }
   if (typeOf === 'string') {
     if (escapeString) {
       return '"' + val.replace(/"|\\/g, '\\$&') + '"';

From 84ac4f69fd2c0e2e5231942921f6ad5dc3b25495 Mon Sep 17 00:00:00 2001
From: "M.K. Safi" <msafi@msafi.com>
Date: Sun, 17 Mar 2019 06:50:57 -0700
Subject: [PATCH 2/2] Address code review comments

---
 CHANGELOG.md                                  |  2 +
 .../src/__tests__/prettyFormat.test.ts        | 41 ++++++++++---------
 2 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 786c91a3a910..b6091eb2283a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@
 
 ### Fixes
 
+- `[pretty-format]` Print `BigInt` as a readable number instead of `{}` [#8138](https://github.com/facebook/jest/pull/8138)
+
 ### Chore & Maintenance
 
 - `[*]` Remove flow from code base ([#8061](https://github.com/facebook/jest/pull/8061))
diff --git a/packages/pretty-format/src/__tests__/prettyFormat.test.ts b/packages/pretty-format/src/__tests__/prettyFormat.test.ts
index 8365d3df7d94..a9275ad50b49 100644
--- a/packages/pretty-format/src/__tests__/prettyFormat.test.ts
+++ b/packages/pretty-format/src/__tests__/prettyFormat.test.ts
@@ -209,40 +209,43 @@ describe('prettyFormat()', () => {
     expect(prettyFormat(val)).toEqual('123');
   });
 
-  it('prints a positive bigint', () => {
-    const val = BigInt(123);
-    expect(prettyFormat(val)).toEqual('123n');
-  });
-
   it('prints a negative number', () => {
     const val = -123;
     expect(prettyFormat(val)).toEqual('-123');
   });
 
-  it('prints a negative bigint', () => {
-    const val = BigInt(-123);
-    expect(prettyFormat(val)).toEqual('-123n');
-  });
-
   it('prints zero', () => {
     const val = 0;
     expect(prettyFormat(val)).toEqual('0');
   });
 
-  it('prints zero bigint', () => {
-    const val = BigInt(0);
-    expect(prettyFormat(val)).toEqual('0n');
-  });
-
   it('prints negative zero', () => {
     const val = -0;
     expect(prettyFormat(val)).toEqual('-0');
   });
 
-  it('prints negative zero bigint', () => {
-    const val = BigInt(-0);
-    expect(prettyFormat(val)).toEqual('0n');
-  });
+  /* global BigInt */
+  if (typeof BigInt === 'function') {
+    it('prints a positive bigint', () => {
+      const val = BigInt(123);
+      expect(prettyFormat(val)).toEqual('123n');
+    });
+
+    it('prints a negative bigint', () => {
+      const val = BigInt(-123);
+      expect(prettyFormat(val)).toEqual('-123n');
+    });
+
+    it('prints zero bigint', () => {
+      const val = BigInt(0);
+      expect(prettyFormat(val)).toEqual('0n');
+    });
+
+    it('prints negative zero bigint', () => {
+      const val = BigInt(-0);
+      expect(prettyFormat(val)).toEqual('0n');
+    });
+  }
 
   it('prints a date', () => {
     const val = new Date(10e11);