chore: migrate jest-diff to TypeScript

CHANGELOG.md

@@ -11,6 +11,7 @@
 - `[diff-sequences]`: Migrate to Typescript ([#7820](https://github.com/facebook/jest/pull/7820))
 - `[jest-get-type]`: Migrate to TypeScript ([#7818](https://github.com/facebook/jest/pull/7818))
 - `[jest-regex-util]`: Migrate to TypeScript ([#7822](https://github.com/facebook/jest/pull/7822))
+- `[jest-diff]`: Migrate to TypeScript ([#7824](https://github.com/facebook/jest/pull/7824))
 
 ### Performance
 

packages/diff-sequences/src/index.ts

@@ -65,7 +65,7 @@ type FoundSubsequence = (
 ) => void;
 
 // Either original functions or wrapped to swap indexes if graph is transposed.
-type Callbacks = {
+export type Callbacks = {
   foundSubsequence: FoundSubsequence;
   isCommon: IsCommon;
 };

packages/jest-diff/package.json

@@ -8,12 +8,17 @@
   },
   "license": "MIT",
   "main": "build/index.js",
+  "types": "build/index.d.ts",
   "dependencies": {
     "chalk": "^2.0.1",
     "diff-sequences": "^24.0.0",
     "jest-get-type": "^24.0.0",
     "pretty-format": "^24.0.0"
   },
+  "devDependencies": {
+    "@types/strip-ansi": "^3.0.0",
+    "strip-ansi": "^5.0.0"
+  },
   "engines": {
     "node": ">= 6"
   },

packages/jest-diff/src/__tests__/diff.test.js → packages/jest-diff/src/__tests__/diff.test.ts

@@ -3,16 +3,17 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
-const stripAnsi = require('strip-ansi');
-const diff = require('../');
+import stripAnsi from 'strip-ansi';
+
+import diff from '../';
+import {DiffOptions} from '../types';
 
 const NO_DIFF_MESSAGE = 'Compared values have no visual difference.';
 
-const stripped = (a, b, options) => stripAnsi(diff(a, b, options));
+const stripped = (a: unknown, b: unknown, options?: DiffOptions) =>
+  stripAnsi(diff(a, b, options) || '');
 
 const unexpanded = {expand: false};
 const expanded = {expand: true};

packages/jest-diff/src/constants.js → packages/jest-diff/src/constants.ts

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
 import chalk from 'chalk';

packages/jest-diff/src/diffStrings.js → packages/jest-diff/src/diffStrings.ts

@@ -3,28 +3,19 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
 import chalk from 'chalk';
-import type {Chalk} from 'chalk';
-import diff from 'diff-sequences';
-import {NO_DIFF_MESSAGE} from './constants.js';
+import diff, {Callbacks} from 'diff-sequences';
+import {NO_DIFF_MESSAGE} from './constants';
+import {DiffOptions} from './types';
 
 const DIFF_CONTEXT_DEFAULT = 5;
 
-export type DiffOptions = {|
-  aAnnotation?: string,
-  bAnnotation?: string,
-  expand?: boolean,
-  contextLines?: number,
-|};
-
-type Original = {|
-  a: string,
-  b: string,
-|};
+type Original = {
+  a: string;
+  b: string;
+};
 
 const fgPatchMark = chalk.yellow;
 const fgDelete = chalk.green;
@@ -35,24 +26,27 @@ const bgCommon = chalk.bgYellow; // edge spaces in common line (even indentation
 const bgInverse = chalk.inverse; // edge spaces in any other lines
 
 // ONLY trailing if expected value is snapshot or multiline string.
-const highlightTrailingSpaces = (line: string, bgColor: Chalk): string =>
+const highlightTrailingSpaces = (line: string, bgColor: typeof chalk): string =>
   line.replace(/\s+$/, bgColor('$&'));
 
 // BOTH leading AND trailing if expected value is data structure.
-const highlightLeadingTrailingSpaces = (line: string, bgColor: Chalk): string =>
+const highlightLeadingTrailingSpaces = (
+  line: string,
+  bgColor: typeof chalk,
+): string =>
   // If line consists of ALL spaces: highlight all of them.
   highlightTrailingSpaces(line, bgColor).replace(
     // If line has an ODD length of leading spaces: highlight only the LAST.
     /^(\s\s)*(\s)(?=[^\s])/,
     '$1' + bgColor('$2'),
   );
 
-type Highlight = (line: string, bgColor: Chalk) => string;
+type Highlight = (line: string, bgColor: typeof chalk) => string;
 
 const getHighlightSpaces = (bothEdges: boolean): Highlight =>
   bothEdges ? highlightLeadingTrailingSpaces : highlightTrailingSpaces;
 
-const getAnnotation = (options: ?DiffOptions): string =>
+const getAnnotation = (options?: DiffOptions): string =>
   fgDelete('- ' + ((options && options.aAnnotation) || 'Expected')) +
   '\n' +
   fgInsert('+ ' + ((options && options.bAnnotation) || 'Received')) +
@@ -134,17 +128,22 @@ const diffExpand = (
   aLinesIn: Array<string>,
   bLinesIn: Array<string>,
 ): string => {
-  const isCommon = (aIndex, bIndex) => aLinesUn[aIndex] === bLinesUn[bIndex];
+  const isCommon: Callbacks['isCommon'] = (aIndex, bIndex) =>
+    aLinesUn[aIndex] === bLinesUn[bIndex];
 
-  const array = [];
+  const array: string[] = [];
   const put = (line: string) => {
     array.push(line);
   };
 
   let aStart = 0;
   let bStart = 0;
 
-  const foundSubsequence = (nCommon, aCommon, bCommon) => {
+  const foundSubsequence: Callbacks['foundSubsequence'] = (
+    nCommon,
+    aCommon,
+    bCommon,
+  ) => {
     formatDelete(aStart, aCommon, aLinesUn, aLinesIn, put);
     formatInsert(bStart, bCommon, bLinesUn, bLinesIn, put);
     formatCommon(nCommon, aCommon, bCommon, aLinesIn, bLinesUn, bLinesIn, put);
@@ -175,7 +174,7 @@ const createPatchMark = (
     `@@ -${aStart + 1},${aEnd - aStart} +${bStart + 1},${bEnd - bStart} @@`,
   );
 
-const getContextLines = (options: ?DiffOptions): number =>
+const getContextLines = (options?: DiffOptions): number =>
   options &&
   typeof options.contextLines === 'number' &&
   options.contextLines >= 0
@@ -193,7 +192,8 @@ const diffNoExpand = (
   bLinesIn: Array<string>,
   nContextLines: number,
 ): string => {
-  const isCommon = (aIndex, bIndex) => aLinesUn[aIndex] === bLinesUn[bIndex];
+  const isCommon: Callbacks['isCommon'] = (aIndex, bIndex) =>
+    aLinesUn[aIndex] === bLinesUn[bIndex];
 
   let iPatchMark = 0; // index of placeholder line for patch mark
   const array = [''];
@@ -215,7 +215,11 @@ const diffNoExpand = (
 
   // Given the number of items and starting indexes of each common subsequence,
   // format any preceding change lines, and then common context lines.
-  const foundSubsequence = (nCommon, aStartCommon, bStartCommon) => {
+  const foundSubsequence: Callbacks['foundSubsequence'] = (
+    nCommon,
+    aStartCommon,
+    bStartCommon,
+  ) => {
     const aEndCommon = aStartCommon + nCommon;
     const bEndCommon = bStartCommon + nCommon;
     isAtEnd = aEndCommon === aLength && bEndCommon === bLength;
@@ -294,7 +298,7 @@ const diffNoExpand = (
 export default (
   a: string,
   b: string,
-  options: ?DiffOptions,
+  options?: DiffOptions,
   original?: Original,
 ): string => {
   if (a === b) {

packages/jest-diff/src/index.js → packages/jest-diff/src/index.ts

@@ -3,17 +3,14 @@
  *
  * 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 {DiffOptions} from './diffStrings';
-
 import prettyFormat from 'pretty-format';
 import chalk from 'chalk';
 import getType from 'jest-get-type';
 import diffStrings from './diffStrings';
 import {NO_DIFF_MESSAGE, SIMILAR_MESSAGE} from './constants';
+import {DiffOptions} from './types';
 
 const {
   AsymmetricMatcher,
@@ -45,7 +42,7 @@ const FALLBACK_FORMAT_OPTIONS_0 = {...FALLBACK_FORMAT_OPTIONS, indent: 0};
 
 // Generate a string that will highlight the difference between two values
 // with green and red. (similar to how github does code diffing)
-function diff(a: any, b: any, options: ?DiffOptions): ?string {
+function diff(a: any, b: any, options?: DiffOptions): string | null {
   if (Object.is(a, b)) {
     return NO_DIFF_MESSAGE;
   }
@@ -98,7 +95,7 @@ function diff(a: any, b: any, options: ?DiffOptions): ?string {
 function comparePrimitive(
   a: number | boolean,
   b: number | boolean,
-  options: ?DiffOptions,
+  options?: DiffOptions,
 ) {
   return diffStrings(
     prettyFormat(a, FORMAT_OPTIONS),
@@ -107,15 +104,15 @@ function comparePrimitive(
   );
 }
 
-function sortMap(map) {
+function sortMap(map: Map<unknown, unknown>) {
   return new Map(Array.from(map.entries()).sort());
 }
 
-function sortSet(set) {
+function sortSet(set: Set<unknown>) {
   return new Set(Array.from(set.values()).sort());
 }
 
-function compareObjects(a: Object, b: Object, options: ?DiffOptions) {
+function compareObjects(a: Object, b: Object, options?: DiffOptions) {
   let diffMessage;
   let hasThrown = false;
 
@@ -153,4 +150,4 @@ function compareObjects(a: Object, b: Object, options: ?DiffOptions) {
   return diffMessage;
 }
 
-module.exports = diff;
+export = diff;

packages/jest-diff/src/types.ts

@@ -0,0 +1,6 @@
+export type DiffOptions = {
+  aAnnotation?: string;
+  bAnnotation?: string;
+  expand?: boolean;
+  contextLines?: number;
+};

packages/jest-diff/tsconfig.json

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

yarn.lock

@@ -1782,6 +1782,11 @@
   resolved "https://registry.yarnpkg.com/@types/string-length/-/string-length-2.0.0.tgz#358ce3ff2e8c2310270ee192ddd6b79b64fed7b2"
   integrity sha512-xFwWZpIWcLsrcVEybzxmxQM/26Snj1gqxmVrelC3We3Nub7q70RCtqTBVQ7nL+315fAcw4BGSFpxvMkhLApKmQ==
 
+"@types/strip-ansi@^3.0.0":
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/@types/strip-ansi/-/strip-ansi-3.0.0.tgz#9b63d453a6b54aa849182207711a08be8eea48ae"
+  integrity sha1-m2PUU6a1SqhJGCIHcRoIvo7qSK4=
+
 "@types/strip-bom@3.0.0":
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/@types/strip-bom/-/strip-bom-3.0.0.tgz#14a8ec3956c2e81edb7520790aecf21c290aebd2"