Definitions for jest's each function

types/jest/index.d.ts

@@ -15,6 +15,7 @@
 //                 Bradley Ayers <https://github.com/bradleyayers>
 //                 Jeff Lau <https://github.com/UselessPickles>
 //                 Andrew Makarov <https://github.com/r3nya>
+//                 Paweł Mikołajczyk <https://github.com/Miklet>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
@@ -209,6 +210,14 @@ declare namespace jest {
         readonly name: string;
     }
 
+    interface Each {
+        (cases: any[]): (name: string, fn: (...args: any[]) => any) => void;
+        (strings: TemplateStringsArray, ...placeholders: any[]): (
+            name: string,
+            fn: (arg: any) => any
+        ) => void;
+    }
+
     /**
      * Creates a test closure
      */
@@ -227,6 +236,7 @@ declare namespace jest {
         only: It;
         skip: It;
         concurrent: It;
+        each: Each;
     }
 
     interface Describe {
@@ -234,6 +244,7 @@ declare namespace jest {
         (name: number | string | Function | FunctionLike, fn: EmptyFunction): void;
         only: Describe;
         skip: Describe;
+        each: Each;
     }
 
     interface MatcherUtils {

types/jest/jest-tests.ts

@@ -760,3 +760,103 @@ describe('toHaveBeenNthCalledWith', () => {
 
     expect(fn).toHaveBeenNthCalledWith(3, "foo");
 });
+
+// https://github.com/DefinitelyTyped/DefinitelyTyped/issues/26368
+
+describe.each([[1, 1, 2], [1, 2, 3], [2, 1, 3]])(
+    ".add(%i, %i)",
+    (a: number, b: number, expected: number) => {
+        test(`returns ${expected}`, () => {
+            expect(a + b).toBe(expected);
+        });
+    }
+);
+
+interface Case {
+    a: number;
+    b: number;
+    expected: number;
+}
+
+describe.each`
+    a    | b    | expected
+    ${1} | ${1} | ${2}
+    ${1} | ${2} | ${3}
+    ${2} | ${1} | ${3}
+`("$a + $b", ({ a, b, expected }: Case) => {
+    test(`returns ${expected}`, () => {
+        expect(a + b).toBe(expected);
+    });
+});
+
+describe.only.each([[1, 1, 2], [1, 2, 3], [2, 1, 3]])(
+    ".add(%i, %i)",
+    (a, b, expected) => {
+        test(`returns ${expected}`, () => {
+            expect(a + b).toBe(expected);
+        });
+    }
+);
+
+describe.only.each`
+    a    | b    | expected
+    ${1} | ${1} | ${2}
+    ${1} | ${2} | ${3}
+    ${2} | ${1} | ${3}
+`("$a + $b", ({ a, b, expected }: Case) => {
+    test(`returns ${expected}`, () => {
+        expect(a + b).toBe(expected);
+    });
+});
+
+describe.skip.each([[1, 1, 2], [1, 2, 3], [2, 1, 3]])(
+    ".add(%i, %i)",
+    (a, b, expected) => {
+        test(`returns ${expected}`, () => {
+            expect(a + b).toBe(expected);
+        });
+    }
+);
+
+describe.skip.each`
+    a    | b    | expected
+    ${1} | ${1} | ${2}
+    ${1} | ${2} | ${3}
+    ${2} | ${1} | ${3}
+`("$a + $b", ({ a, b, expected }: Case) => {
+    test(`returns ${expected}`, () => {
+        expect(a + b).toBe(expected);
+    });
+});
+
+test.each([[1, 1, 2], [1, 2, 3], [2, 1, 3]])(
+    ".add(%i, %i)",
+    (a, b, expected) => {
+        expect(a + b).toBe(expected);
+    }
+);
+
+test.each`
+    a    | b    | expected
+    ${1} | ${1} | ${2}
+    ${1} | ${2} | ${3}
+    ${2} | ${1} | ${3}
+`("returns $expected when $a is added $b", ({ a, b, expected }: Case) => {
+    expect(a + b).toBe(expected);
+});
+
+test.only.each([[1, 1, 2], [1, 2, 3], [2, 1, 3]])(
+    ".add(%i, %i)",
+    (a, b, expected) => {
+        expect(a + b).toBe(expected);
+    }
+);
+
+test.only.each`
+    a    | b    | expected
+    ${1} | ${1} | ${2}
+    ${1} | ${2} | ${3}
+    ${2} | ${1} | ${3}
+`("returns $expected when $a is added $b", ({ a, b, expected }: Case) => {
+    expect(a + b).toBe(expected);
+});