├── .editorconfig ├── .gitattributes ├── .github ├── funding.yml ├── security.md └── workflows │ └── main.yml ├── .gitignore ├── .npmrc ├── fixture.jpg ├── fixture.png ├── index.d.ts ├── index.js ├── index.test-d.ts ├── license ├── package.json ├── readme.md └── test.js /.editorconfig: -------------------------------------------------------------------------------- 1 | root = true 2 | 3 | [*] 4 | indent_style = tab 5 | end_of_line = lf 6 | charset = utf-8 7 | trim_trailing_whitespace = true 8 | insert_final_newline = true 9 | 10 | [*.yml] 11 | indent_style = space 12 | indent_size = 2 13 | -------------------------------------------------------------------------------- /.gitattributes: -------------------------------------------------------------------------------- 1 | * text=auto eol=lf 2 | -------------------------------------------------------------------------------- /.github/funding.yml: -------------------------------------------------------------------------------- 1 | github: sindresorhus 2 | open_collective: sindresorhus 3 | tidelift: npm/is-png 4 | custom: https://sindresorhus.com/donate 5 | -------------------------------------------------------------------------------- /.github/security.md: -------------------------------------------------------------------------------- 1 | # Security Policy 2 | 3 | To report a security vulnerability, please use the [Tidelift security contact](https://tidelift.com/security). Tidelift will coordinate the fix and disclosure. 4 | -------------------------------------------------------------------------------- /.github/workflows/main.yml: -------------------------------------------------------------------------------- 1 | name: CI 2 | on: 3 | - push 4 | - pull_request 5 | jobs: 6 | test: 7 | name: Node.js ${{ matrix.node-version }} 8 | runs-on: ubuntu-latest 9 | strategy: 10 | fail-fast: false 11 | matrix: 12 | node-version: 13 | - 16 14 | steps: 15 | - uses: actions/checkout@v2 16 | - uses: actions/setup-node@v2 17 | with: 18 | node-version: ${{ matrix.node-version }} 19 | - run: npm install 20 | - run: npm test 21 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | node_modules 2 | yarn.lock 3 | -------------------------------------------------------------------------------- /.npmrc: -------------------------------------------------------------------------------- 1 | package-lock=false 2 | -------------------------------------------------------------------------------- /fixture.jpg: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/sindresorhus/is-png/f42aae226eb0579c1ad19a70dfafb9477cd344d1/fixture.jpg -------------------------------------------------------------------------------- /fixture.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/sindresorhus/is-png/f42aae226eb0579c1ad19a70dfafb9477cd344d1/fixture.png -------------------------------------------------------------------------------- /index.d.ts: -------------------------------------------------------------------------------- 1 | /** 2 | Check if a Buffer/Uint8Array is a [PNG](https://en.wikipedia.org/wiki/Portable_Network_Graphics) image. 3 | 4 | @param buffer - The buffer to check. It only needs the first 8 bytes. 5 | @returns Whether `buffer` contains a PNG image. 6 | 7 | @example 8 | ``` 9 | // Node.js: 10 | import {readChunk} from 'read-chunk'; 11 | import isPng from 'is-png'; 12 | 13 | const buffer = await readChunk('unicorn.png', {length: 8}); 14 | 15 | isPng(buffer); 16 | //=> true 17 | ``` 18 | 19 | @example 20 | ``` 21 | import isPng from 'is-png'; 22 | 23 | // Browser: 24 | const response = await fetch('unicorn.png'); 25 | const buffer = await response.arrayBuffer(); 26 | 27 | isPng(new Uint8Array(buffer)); 28 | //=> true 29 | ``` 30 | */ 31 | export default function isPng(buffer: Uint8Array): boolean; 32 | -------------------------------------------------------------------------------- /index.js: -------------------------------------------------------------------------------- 1 | export default function isPng(buffer) { 2 | if (!buffer || buffer.length < 8) { 3 | return false; 4 | } 5 | 6 | return buffer[0] === 0x89 7 | && buffer[1] === 0x50 8 | && buffer[2] === 0x4E 9 | && buffer[3] === 0x47 10 | && buffer[4] === 0x0D 11 | && buffer[5] === 0x0A 12 | && buffer[6] === 0x1A 13 | && buffer[7] === 0x0A; 14 | } 15 | -------------------------------------------------------------------------------- /index.test-d.ts: -------------------------------------------------------------------------------- 1 | import {Buffer} from 'node:buffer'; 2 | import {expectType} from 'tsd'; 3 | import isPng from './index.js'; 4 | 5 | expectType(isPng(new Uint8Array(0))); 6 | expectType(isPng(Buffer.from(''))); 7 | 8 | const response = await fetch('unicorn.png'); 9 | const buffer = await response.arrayBuffer(); 10 | 11 | isPng(new Uint8Array(buffer)); 12 | -------------------------------------------------------------------------------- /license: -------------------------------------------------------------------------------- 1 | MIT License 2 | 3 | Copyright (c) Sindre Sorhus (https://sindresorhus.com) 4 | 5 | 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: 6 | 7 | The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. 8 | 9 | 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. 10 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "is-png", 3 | "version": "3.0.1", 4 | "description": "Check if a Buffer/Uint8Array is a PNG image", 5 | "license": "MIT", 6 | "repository": "sindresorhus/is-png", 7 | "funding": "https://github.com/sponsors/sindresorhus", 8 | "author": { 9 | "name": "Sindre Sorhus", 10 | "email": "sindresorhus@gmail.com", 11 | "url": "https://sindresorhus.com" 12 | }, 13 | "type": "module", 14 | "exports": "./index.js", 15 | "engines": { 16 | "node": ">=12" 17 | }, 18 | "scripts": { 19 | "test": "xo && ava && tsd" 20 | }, 21 | "files": [ 22 | "index.js", 23 | "index.d.ts" 24 | ], 25 | "keywords": [ 26 | "png", 27 | "portable", 28 | "network", 29 | "graphics", 30 | "image", 31 | "picture", 32 | "photo", 33 | "type", 34 | "detect", 35 | "check", 36 | "is", 37 | "exif", 38 | "binary", 39 | "buffer", 40 | "uint8array" 41 | ], 42 | "devDependencies": { 43 | "@types/node": "^16.7.10", 44 | "ava": "^3.15.0", 45 | "read-chunk": "^4.0.1", 46 | "tsd": "^0.17.0", 47 | "xo": "^0.44.0" 48 | } 49 | } 50 | -------------------------------------------------------------------------------- /readme.md: -------------------------------------------------------------------------------- 1 | # is-png 2 | 3 | > Check if a Buffer/Uint8Array is a [PNG](https://en.wikipedia.org/wiki/Portable_Network_Graphics) image 4 | 5 | ## Install 6 | 7 | ``` 8 | $ npm install is-png 9 | ``` 10 | 11 | ## Usage 12 | 13 | ##### Node.js 14 | 15 | ```js 16 | import {readChunk} from 'read-chunk'; 17 | import isPng from 'is-png'; 18 | 19 | const buffer = await readChunk('unicorn.png', {length: 8}); 20 | 21 | isPng(buffer); 22 | //=> true 23 | ``` 24 | 25 | ##### Browser 26 | 27 | ```js 28 | import isPng from 'is-png'; 29 | 30 | const response = await fetch('unicorn.png'); 31 | const buffer = await response.arrayBuffer(); 32 | 33 | isPng(new Uint8Array(buffer)); 34 | //=> true 35 | ``` 36 | 37 | ## API 38 | 39 | ### isPng(buffer) 40 | 41 | Accepts a Buffer (Node.js) or Uint8Array. Returns a `boolean` of whether `buffer` is a PNG image. 42 | 43 | #### buffer 44 | 45 | The buffer to check. It only needs the first 8 bytes. 46 | 47 | ## Related 48 | 49 | - [file-type](https://github.com/sindresorhus/file-type) - Detect the file type of a Buffer/Uint8Array/ArrayBuffer 50 | -------------------------------------------------------------------------------- /test.js: -------------------------------------------------------------------------------- 1 | import test from 'ava'; 2 | import {readChunkSync} from 'read-chunk'; 3 | import isPng from './index.js'; 4 | 5 | const check = filename => isPng(readChunkSync(filename, {length: 8})); 6 | 7 | test('main', t => { 8 | t.true(check('fixture.png')); 9 | t.false(check('fixture.jpg')); 10 | }); 11 | --------------------------------------------------------------------------------