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Gathering detailed insights and metrics for magic-bytes.js

magic-bytes.js - 1.12.1 | npmpackage.info

magic-bytes.js

A library for detecting file types.

1.12.1

145

MIT

TypeScript

3.78 kB

16,112,014 4.7

Installations

npm install magic-bytes.js

Developer Guide

BETA

Typescript

Yes

Module System

CommonJS

Node Version

18.20.8

NPM Version

10.1.0 Score

99.5

Supply Chain

99.6

Quality

78.5

Maintenance

100

Vulnerability

100

License

Pull Requests

Open

6

Total

43

Closed

7

Merged

30

Issues

Open

3

Total

22

Closed

19

Releases

v1.12.1

Updated on Apr 26, 2025

v1.12.0

Updated on Apr 25, 2025

v1.11.0

Updated on Apr 17, 2025

v1.10.0

Updated on Feb 29, 2024

v1.9.0

Updated on Feb 29, 2024

v1.8.0

Updated on Jan 11, 2024

View All 14 releases

Languages

TypeScript

HTML

CSS

JavaScript

TypeScript (87.64%)

HTML (6.7%)

CSS (3.34%)

JavaScript (2.32%)

Developer

LarsKoelpin

Download Statistics

Total Downloads

16,112,014

Last Day

25,595

Last Week

269,794

Last Month

1,138,860

Last Year

10,580,015

GitHub Statistics

MIT License

145 Stars

226 Commits

29 Forks

1 Watchers

7 Branches

16 Contributors

Updated on Jun 24, 2025

Bundle Size

19.84 kB

Minified

3.78 kB

Minified + Gzipped

Bundlephobia

Maintainers

View All 16 Contributors

Package Meta Information

Latest Version

1.12.1

Package Id

magic-bytes.js@1.12.1

Unpacked Size

55.16 kB

Size

11.42 kB

File Count

NPM Version

10.1.0

Node Version

18.20.8

Published on

Apr 26, 2025

Total Downloads

Cumulative downloads

Total Downloads

16,112,014

Last Day

-1.4%

25,595

Compared to previous day

Last Week

-0.9%

269,794

Compared to previous week

Last Month

1,138,860

Compared to previous month

Last Year

119.3%

10,580,015

Compared to previous year

Weekly Downloads

Monthly Downloads

Yearly Downloads

Magic bytes

Magic Bytes is a javascript library analyzing the first bytes of a file to tell you its type. Use it inside your browser or serversided using nodejs.

The procedure is based on https://en.wikipedia.org/wiki/List_of_file_signatures.

[!NOTE]
A small note on versioning. Strictly speaking, each new filetype which is supported by this library can break someones' API. Please note that this library adds new filetypes with minor release. This means files, which validate to "null" in some versions, may find a result in a new version.

Or in some cases the library will find more results, than before. So don't depend on the found-array size in any shape or form. Filetypes will not be removed though.

Installation

Run npm install magic-bytes.js

Interactive example

There is an interactive example present at https://larskoelpin.github.io/magic-bytes/.

Usage

The following functions are available:

filetypeinfo(bytes: number[]) Contains typeinformation like name, extension and mime type: [{typename: "zip"}, {typename: "jar"}]
filetypename(bytes: number[]) : Contains type names only: ["zip", "jar"]
filetypemime(bytes: number[]) : Contains type mime types only: ["application/zip", "application/jar"]
filetypeextension(bytes: number[]) : Contains type extensions only: ["zip", "jar"]
register(fileType: string, string[]): registers a custom signature

Both function return an empty array [] otherwise, which means it could not detect the file signature. Keep in mind that txt files for example fall in this category.

You don't have to load the whole file in memory. For validating a file uploaded to S3 using Lambda for example, it may be
enough to load the files first 100 bytes and validate against them. This is especially useful for big files.

see examples for practical usage.

On server:

1import filetype from 'magic-bytes.js'
2
3filetype(fs.readFileSync("myimage.png")) // ["png"]

To run an HTML-Example checkout the project and run

npm install; npm run example

This opens an HTML example using magic bytes as a window variable. It kinda looks like that.

1<input type="file" id="file" />
2
3 <script src="node_modules/magic-bytes.js/dist/browser.js" type="application/javascript"></script>
4<script>
5    document.getElementById("file").addEventListener('change', (event, x) => {
6      const fileReader = new FileReader();
7      fileReader.onloadend = (f) => {
8        const bytes = new Uint8Array(f.target.result);
9        console.log("Possible filetypes: " + filetypeinfo(bytes))
10      }
11      fileReader.readAsArrayBuffer(event.target.files[0])
12    })
13</script>

Tests

Run npm test

Example

See examples/

How does it work

The create-snapshot.js creates a new tree. The tree has a similar shape to the following

1{
2  "0x47": {
3    "0x49": {
4      "0x46": {
5        "0x38": {
6          "0x37": {
7            "0x61": {
8              "matches": [
9                {
10                  "typename": "gif",
11                  "mime": "image/gif",
12                  "extension": "gif"
13                }
14              ]
15            }
16          },
17        }
18      }
19    }
20  }
21}

It acts as a giant lookup map for the given byte signatures.

No vulnerabilities found.

10

Maintained

Determines if the project is "actively maintained".

10

Dangerous-Workflow

Determines if the project's GitHub Action workflows avoid dangerous patterns.

10

Binary-Artifacts

Determines if the project has generated executable (binary) artifacts in the source repository.

10

License

Determines if the project has defined a license.

9

Token-Permissions

Determines if the project's workflows follow the principle of least privilege.

3

Code-Review

Determines if the project requires human code review before pull requests (aka merge requests) are merged.

2

Pinned-Dependencies

Determines if the project has declared and pinned the dependencies of its build process.

0

CII-Best-Practices

Determines if the project has an OpenSSF (formerly CII) Best Practices Badge.

0

Security-Policy

Determines if the project has published a security policy.

0

Fuzzing

Determines if the project uses fuzzing.

0

Branch-Protection

Determines if the default and release branches are protected with GitHub's branch protection settings.

0

SAST

Determines if the project uses static code analysis.

0

Vulnerabilities

Determines if the project has open, known unfixed vulnerabilities.

Score

4.7

/10

Last Scanned on 2025-06-30

The Open Source Security Foundation is a cross-industry collaboration to improve the security of open source software (OSS). The Scorecard provides security health metrics for open source projects.

Learn More

Other packages similar to magic-bytes.js

Other packages similar to magic-bytes.js

magic-bytes.js

Installations

Developer Guide

Yes

CommonJS

18.20.8

10.1.0

Score

Pull Requests

6

43

7

30

Issues

3

22

19

Releases

Languages

Developer

LarsKoelpin

Download Statistics

GitHub Statistics

Bundle Size

19.84 kB

3.78 kB

Maintainers

Package Meta Information

Total Downloads

16,112,014

Weekly Downloads

Monthly Downloads

Yearly Downloads

Dev Dependencies

Magic bytes

Installation

Interactive example

Usage

Tests

Example

How does it work

10

10

10

10

9

3

2

0

0

0

0

0

0

4.7

/10