chore: migrate jest-matcher-util to TypeScript

CHANGELOG.md

@@ -16,6 +16,7 @@
 - `[jest-diff]`: Migrate to TypeScript ([#7824](https://github.com/facebook/jest/pull/7824))
 - `[jest-leak-detector]`: Migrate to TypeScript ([#7825](https://github.com/facebook/jest/pull/7825))
 - `[jest-changed-files]`: Migrate to TypeScript ([#7827](https://github.com/facebook/jest/pull/7827))
+- `[jest-matcher-utils]`: Migrate to TypeScript ([#7835](https://github.com/facebook/jest/pull/7835))
 
 ### Performance
 

packages/jest-matcher-utils/src/__tests__/index.test.js → packages/jest-matcher-utils/src/__tests__/index.test.ts

@@ -37,7 +37,7 @@ describe('.stringify()', () => {
   });
 
   test('circular references', () => {
-    const a = {};
+    const a: any = {};
     a.a = a;
     expect(stringify(a)).toBe('{"a": [Circular]}');
   });
@@ -75,8 +75,8 @@ describe('.stringify()', () => {
   });
 
   test('reduces maxDepth if stringifying very large objects', () => {
-    const big = {a: 1, b: {}};
-    const small = {a: 1, b: {}};
+    const big: any = {a: 1, b: {}};
+    const small: any = {a: 1, b: {}};
     for (let i = 0; i < 10000; i += 1) {
       big.b[i] = 'test';
     }
@@ -93,18 +93,21 @@ describe('.stringify()', () => {
 describe('.ensureNumbers()', () => {
   test('dont throw error when variables are numbers', () => {
     expect(() => {
+      // @ts-ignore
       ensureNumbers(1, 2);
     }).not.toThrow();
   });
 
   test('throws error when expected is not a number', () => {
     expect(() => {
+      // @ts-ignore
       ensureNumbers(1, 'not_a_number');
     }).toThrowErrorMatchingSnapshot();
   });
 
   test('throws error when received is not a number', () => {
     expect(() => {
+      // @ts-ignore
       ensureNumbers('not_a_number', 3);
     }).toThrowErrorMatchingSnapshot();
   });
@@ -113,6 +116,7 @@ describe('.ensureNumbers()', () => {
 describe('.ensureNoExpected()', () => {
   test('dont throw error when undefined', () => {
     expect(() => {
+      // @ts-ignore
       ensureNoExpected(undefined);
     }).not.toThrow();
   });

packages/jest-matcher-utils/src/index.js → packages/jest-matcher-utils/src/index.ts

@@ -3,12 +3,8 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
-import type {MatcherHintOptions} from 'types/Matchers';
-
 import chalk from 'chalk';
 import jestDiff from 'jest-diff';
 import getType from 'jest-get-type';
@@ -31,6 +27,14 @@ const PLUGINS = [
   AsymmetricMatcher,
 ];
 
+export type MatcherHintOptions = {
+  comment?: string;
+  isDirectExpectCall?: boolean;
+  isNot?: boolean;
+  promise?: string;
+  secondArgument?: string;
+};
+
 export const EXPECTED_COLOR = chalk.green;
 export const RECEIVED_COLOR = chalk.red;
 const DIM_COLOR = chalk.dim;
@@ -60,7 +64,7 @@ export const SUGGEST_TO_CONTAIN_EQUAL = chalk.dim(
   'Looks like you wanted to test for object/array equality with the stricter `toContain` matcher. You probably need to use `toContainEqual` instead.',
 );
 
-export const stringify = (object: any, maxDepth?: number = 10): string => {
+export const stringify = (object: any, maxDepth: number = 10): string => {
   const MAX_LENGTH = 10000;
   let result;
 
@@ -184,7 +188,7 @@ export const pluralize = (word: string, count: number) =>
 // return function which given each string, returns the label:
 // string, colon, space, and enough padding spaces to align the value.
 
-type PrintLabel = string => string;
+type PrintLabel = (string: string) => string;
 
 export const getLabelPrinter = (...strings: Array<string>): PrintLabel => {
   const maxLength = strings.reduce(

packages/jest-matcher-utils/tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "build"
+  },
+  "references": [
+    {"path": "../jest-diff"},
+    {"path": "../jest-get-type"},
+    {"path": "../pretty-format"}
+  ]
+}