Implement @fresha/json-pointer

Author: mykulyak

package-lock.json

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+{
+  "extends": ["@fresha"],
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "project": ["./tsconfig.eslint.json"]
+  }
+}

packages/json-pointer/.eslintrc

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+MIT License
+
+Copyright (c) 2022 Fresha
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/json-pointer/LICENSE

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+# @fresha/json-pointer
+
+This is an implementation of RFC-6901 JSON Pointer.
+
+##

packages/json-pointer/README.md

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+module.exports = require('@fresha/jest-config');

packages/json-pointer/jest.config.js

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+{
+  "name": "@fresha/json-pointer",
+  "version": "0.1.0",
+  "description": "Implementation of the JSON Pointer specification",
+  "main": "build/index.js",
+  "types": "build/index.d.ts",
+  "scripts": {
+    "build": "tsc",
+    "build:watch": "tsc --watch",
+    "check": "run-s lint test",
+    "check:fix": "run-s lint:fix test",
+    "clean": "rimraf ./build",
+    "eslint": "eslint ./src",
+    "eslint:fix": "eslint ./src --fix",
+    "lint": "run-s eslint typecheck",
+    "lint:fix": "run-s eslint:fix typecheck",
+    "prebuild": "npm run clean",
+    "prebuild:watch": "npm run clean",
+    "test": "jest",
+    "typecheck": "tsc --noEmit"
+  },
+  "files": [
+    "build/",
+    "package.json",
+    "LICENSE",
+    "README.md"
+  ],
+  "keywords": [
+    "JSON",
+    "JSON pointer"
+  ],
+  "author": "Fresha Engineering",
+  "contributors": [
+    {
+      "name": "Andriy Mykulyak",
+      "email": "andriy@fresha.com",
+      "url": "https://github.com/mykulyak"
+    }
+  ],
+  "maintainers": [
+    {
+      "name": "Andriy Mykulyak",
+      "email": "andriy@fresha.com",
+      "url": "https://github.com/mykulyak"
+    }
+  ],
+  "license": "MIT",
+  "devDependencies": {
+    "@fresha/api-tools-core": "0.1.0",
+    "@fresha/eslint-config": "0.1.0",
+    "@fresha/jest-config": "0.1.0",
+    "@fresha/typescript-config": "0.1.0",
+    "typescript": "^4.7.2"
+  }
+}

packages/json-pointer/package.json

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+import { JSONPointer } from './JSONPointer';
+
+import type { JSONValue } from '@fresha/api-tools-core';
+
+test('constructor', () => {
+  expect(new JSONPointer('')).toBeInstanceOf(JSONPointer);
+  expect(new JSONPointer('/')).toBeInstanceOf(JSONPointer);
+  expect(new JSONPointer('/x/y/z')).toBeInstanceOf(JSONPointer);
+  expect(() => new JSONPointer('a/b/c')).toThrow();
+});
+
+test('get', () => {
+  const testObj: JSONValue = {
+    numberProp: 1,
+    objProp: {
+      strProp: 'str',
+      boolProp: true,
+    },
+    arrProp: [12, '34', { subProp: 'cdd' }],
+    nullProp: null,
+  };
+
+  expect(new JSONPointer('').get(testObj)).toBe(testObj);
+  expect(new JSONPointer('/numberProp').get(testObj)).toBe(1);
+  expect(new JSONPointer('/objProp/strProp').get(testObj)).toBe('str');
+  expect(new JSONPointer('/arrProp/2/subProp').get(testObj)).toBe('cdd');
+  expect(new JSONPointer('/nullProp').get(testObj)).toBe(null);
+  expect(new JSONPointer('/numberProp/nonExistend').get(testObj)).toBe(undefined);
+  expect(new JSONPointer('/objProp/nonExistent').get(testObj)).toBe(undefined);
+});
+
+test('toString', () => {
+  expect(new JSONPointer('').toString()).toBe('');
+  expect(new JSONPointer('/prop/1/arr/obj/str/num/bool').toString()).toBe(
+    '/prop/1/arr/obj/str/num/bool',
+  );
+});

packages/json-pointer/src/JSONPointer.test.ts

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+import assert from 'assert';
+
+import type { JSONObject, JSONValue } from '@fresha/api-tools-core';
+
+export class JSONPointer {
+  private readonly segments: string[];
+
+  constructor(segments: string | string[]) {
+    this.segments = typeof segments === 'string' ? segments.split('/') : segments;
+    assert.equal(this.segments[0], '');
+  }
+
+  get(obj: JSONValue): JSONValue | undefined {
+    if (this.segments.length === 1) {
+      return obj;
+    }
+    let res: JSONValue | undefined = obj;
+    for (const seg of this.segments.slice(1)) {
+      if (seg) {
+        res = res != null ? (res as JSONObject)[seg] : undefined;
+        if (res === undefined) {
+          break;
+        }
+      }
+    }
+    return res;
+  }
+
+  toString(): string {
+    return this.segments.join('/');
+  }
+}

packages/json-pointer/src/JSONPointer.ts

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+import { JSONPointerResolver } from './JSONPointerResolver';
+
+test('get', () => {
+  const testObj = {
+    numberProp: 1,
+    objProp: {
+      strProp: 'str',
+      boolProp: true,
+    },
+    arrProp: [12, '34', { subProp: 'cdd' }],
+    nullProp: null,
+  };
+  const resolver = new JSONPointerResolver(testObj);
+
+  expect(resolver.get('/')).toBe(testObj);
+  expect(resolver.get('/objProp/strProp')).toBe('str');
+});

packages/json-pointer/src/JSONPointerResolver.test.ts

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+import { JSONPointer } from './JSONPointer';
+
+import type { JSONValue } from '@fresha/api-tools-core';
+
+export class JSONPointerResolver {
+  private readonly obj: JSONValue;
+
+  constructor(obj: JSONValue) {
+    this.obj = obj;
+  }
+
+  get(ptrOrStr: string | string[] | JSONPointer): JSONValue | undefined {
+    const ptr = ptrOrStr instanceof JSONPointer ? ptrOrStr : new JSONPointer(ptrOrStr);
+    return ptr.get(this.obj);
+  }
+}