@gagandeep023/json-view

Zero-dependency JSON tools for formatting, diffing, and un-stringifying JSON. Works in Node.js and the browser.

Installation

npm:

npm install @gagandeep023/json-view

yarn:

yarn add @gagandeep023/json-view

pnpm:

pnpm add @gagandeep023/json-view

Quick Start

import { formatJSON, diffJSON, parseStringified } from '@gagandeep023/json-view';

// Format JSON with 2-space indent
const result = formatJSON('{"name":"Alice","age":30}');
console.log(result.formatted);

// Diff two objects
const diff = diffJSON({ a: 1 }, { a: 2, b: 3 });
console.log(diff.stats); // { added: 1, removed: 0, modified: 1 }

// Un-stringify nested JSON
const parsed = parseStringified('"{\\"key\\":\\"value\\"}"');
console.log(parsed.parsed); // { key: "value" }

API Reference

formatJSON(input, options?)

Parse and beautify a JSON string with configurable indentation and optional key sorting.

Parameters:

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | input | string | Yes | - | Raw JSON string to format | | options.indent | number | No | 2 | Number of spaces for indentation | | options.sortKeys | boolean | No | false | Sort object keys alphabetically (recursive) |

Returns: FormatResult

const result = formatJSON('{"z":3,"a":1}', { indent: 4, sortKeys: true });
// result.success === true
// result.formatted === '{\n    "a": 1,\n    "z": 3\n}'

minifyJSON(input)

Compact a JSON string into a single line with no whitespace.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | input | string | Yes | JSON string to minify |

Returns: FormatResult

const result = minifyJSON('{\n  "a": 1,\n  "b": 2\n}');
// result.formatted === '{"a":1,"b":2}'

validateJSON(input)

Check if a string is valid JSON. Returns error details with line/column on failure.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | input | string | Yes | JSON string to validate |

Returns: FormatResult

const result = validateJSON('{"a": }');
// result.success === false
// result.error === "Expected value at line 1, column 7"
// result.errorLocation === { line: 1, column: 7 }

diffJSON(oldVal, newVal)

Deep recursive comparison of two parsed JSON values. Handles objects, arrays, primitives, null, and type mismatches. Max depth: 50 levels.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | oldVal | unknown | Yes | Original parsed JSON value | | newVal | unknown | Yes | Modified parsed JSON value |

Returns: DiffResult

const diff = diffJSON(
  { user: { name: 'Alice', role: 'admin' } },
  { user: { name: 'Bob', role: 'admin', active: true } }
);
// diff.hasChanges === true
// diff.stats === { added: 1, removed: 0, modified: 1 }
// diff.changes[0] === { path: 'user.name', type: 'modified', oldValue: 'Alice', newValue: 'Bob' }
// diff.changes[1] === { path: 'user.active', type: 'added', newValue: true }

flattenDiff(changes)

Flatten a tree of DiffNode children into a linear array.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | changes | DiffNode[] | Yes | Array of diff nodes (potentially with children) |

Returns: DiffNode[]

parseStringified(input)

Iteratively JSON.parse a value until it stops being a string. Useful for un-escaping double/triple-stringified JSON from logs, APIs, or databases. Max nesting depth: 10.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | input | string | Yes | Stringified JSON to unwrap |

Returns: ParseStringifiedResult

// Double-stringified JSON (common in logs)
const input = JSON.stringify(JSON.stringify({ key: 'value' }));
const result = parseStringified(input);
// result.parsed === { key: 'value' }
// result.nestingLevel === 1

TypeScript

Full TypeScript support with exported types:

import type {
  FormatOptions,
  FormatResult,
  DiffChangeType,
  DiffNode,
  DiffResult,
  ParseStringifiedResult,
} from '@gagandeep023/json-view';

License

MIT