Merge pull request #203 from webdeveric/dev

Added `isJSONable()`

Author: webdeveric

package.json

@@ -66,7 +66,7 @@
     "url": "https://github.com/webdeveric/utils/issues"
   },
   "homepage": "https://github.com/webdeveric/utils/#readme",
-  "packageManager": "pnpm@10.14.0+sha512.ad27a79641b49c3e481a16a805baa71817a04bbe06a38d17e60e2eaee83f6a146c6a688125f5792e48dd5ba30e7da52a5cda4c3992b9ccf333f9ce223af84748",
+  "packageManager": "pnpm@10.15.1+sha512.34e538c329b5553014ca8e8f4535997f96180a1d0f614339357449935350d924e22f8614682191264ec33d1462ac21561aff97f6bb18065351c162c7e8f6de67",
   "scripts": {
     "clean": "rimraf ./dist/",
     "prebuild": "pnpm clean",
@@ -87,21 +87,21 @@
   "devDependencies": {
     "@commitlint/config-conventional": "^19.8.1",
     "@commitlint/types": "^19.8.1",
-    "@types/node": "^22.17.2",
+    "@types/node": "^22.18.0",
     "@vitest/coverage-v8": "^3.2.4",
     "@webdeveric/eslint-config-ts": "^0.11.0",
     "@webdeveric/prettier-config": "^0.3.0",
     "commitlint": "^19.8.1",
     "commitlint-plugin-cspell": "^0.3.0",
     "conventional-changelog-conventionalcommits": "^9.1.0",
-    "cspell": "^9.2.0",
+    "cspell": "^9.2.1",
     "eslint": "^8.57.1",
     "eslint-config-prettier": "^10.1.8",
     "eslint-import-resolver-typescript": "^4.4.4",
     "eslint-plugin-import": "^2.32.0",
     "husky": "^9.1.7",
     "jsdom": "^26.1.0",
-    "lint-staged": "^16.1.5",
+    "lint-staged": "^16.1.6",
     "prettier": "^3.6.2",
     "rimraf": "^6.0.1",
     "semantic-release": "^24.2.7",

pnpm-lock.yaml

@@ -16,32 +16,34 @@ export type CommentOptions = {
   type?: CommentType | `${CommentType}`;
 } & Partial<CommentParts>;
 
-const commentTypes: Record<CommentType, CommentParts> = {
-  [CommentType.Block]: {
-    commentStart: '/**\n',
-    commentEnd: '\n */',
-    lineStart: ' * ',
-    lineEnd: '',
-  },
-  [CommentType.Legal]: {
-    commentStart: '/*!\n',
-    commentEnd: '\n */',
-    lineStart: ' * ',
-    lineEnd: '',
-  },
-  [CommentType.Single]: {
-    commentStart: '',
-    commentEnd: '',
-    lineStart: '// ',
-    lineEnd: '',
-  },
-  [CommentType.HTML]: {
-    commentStart: '<!-- ',
-    commentEnd: ' -->',
-    lineStart: '',
-    lineEnd: '',
-  },
-};
+function getCommentParts(type: CommentType | `${CommentType}`): CommentParts {
+  return {
+    [CommentType.Block]: {
+      commentStart: '/**\n',
+      commentEnd: '\n */',
+      lineStart: ' * ',
+      lineEnd: '',
+    },
+    [CommentType.Legal]: {
+      commentStart: '/*!\n',
+      commentEnd: '\n */',
+      lineStart: ' * ',
+      lineEnd: '',
+    },
+    [CommentType.Single]: {
+      commentStart: '',
+      commentEnd: '',
+      lineStart: '// ',
+      lineEnd: '',
+    },
+    [CommentType.HTML]: {
+      commentStart: '<!-- ',
+      commentEnd: ' -->',
+      lineStart: '',
+      lineEnd: '',
+    },
+  }[type];
+}
 
 export function comment(text: string, options?: CommentOptions): string {
   if (!text) {
@@ -56,7 +58,7 @@ export function comment(text: string, options?: CommentOptions): string {
     lineStart = '',
     lineEnd = '',
   } = {
-    ...commentTypes[type],
+    ...getCommentParts(type),
     ...partOptions,
   };
 

src/comment.ts

@@ -21,6 +21,7 @@ export * from './isInteger.js';
 export * from './isIntString.js';
 export * from './isISODateString.js';
 export * from './isIterable.js';
+export * from './isJSONable.js';
 export * from './isLengthAware.js';
 export * from './isNonNullable.js';
 export * from './isNull.js';

src/predicate/index.ts

@@ -0,0 +1,11 @@
+import type { JsonValue } from '../types/common.js';
+
+export const isJSONable = (input: unknown): input is { toJSON: (key: string) => JsonValue } => {
+  return (
+    input !== null &&
+    typeof input === 'object' &&
+    'toJSON' in input &&
+    typeof input.toJSON === 'function' &&
+    input.toJSON.length <= 1 // maybe uses the `key` argument
+  );
+};

src/predicate/isJSONable.ts

@@ -1,10 +1,7 @@
-const isWhitespaceOnly = (input: string): boolean => /^\s*$/.test(input);
-
 export function trimIndentation(input: string): string {
   const lines = input.split('\n');
-  const whiteSpace = lines.find((line) => !isWhitespaceOnly(line))?.match(/^(?<whiteSpace>\s*)/)?.groups?.[
-    'whiteSpace'
-  ];
+  // Find indentation on first line that isn't whitespace only.
+  const whiteSpace = lines.find((line) => !/^\s*$/.test(line))?.match(/^(?<whiteSpace>\s*)/)?.groups?.['whiteSpace'];
 
   if (whiteSpace) {
     const wsPattern = new RegExp(`^${whiteSpace}`);

src/trimIndentation.ts

@@ -0,0 +1,21 @@
+import { describe, expect, it } from 'vitest';
+
+import { isJSONable } from '../../src/predicate/isJSONable.js';
+
+import type { JsonValue } from '../../src/index.js';
+
+describe('isJSONable()', () => {
+  it('should return true for objects with a toJSON method', () => {
+    const obj = {
+      toJSON(key: string): JsonValue {
+        return { key };
+      },
+    };
+
+    expect(isJSONable(obj)).toBe(true);
+  });
+
+  it.each([{}, null, true, 'test', 123])('should return false for objects without a toJSON method: %j', (input) => {
+    expect(isJSONable(input)).toBe(false);
+  });
+});