filev

A simple and extensible file validation library for browser and server environments.

A lightweight and extensible file validation library for both browser and server environments.
Supports type, size, and extension rules — ideal for file uploads in modern web applications.

Features

• 🎯 Validate file type, size, and extension
• 🔒 Built with TypeScript for full type safety
• 🌍 Works seamlessly in both browser and server-side environments
• 🧩 Modular rule design for easy customization

Installation

npm install filev

Usage

Validate single file

import { FileValidator } from "filev";

const validated = FileValidator.validate({
  file: myFile,
  maxSize: 5 * 1024 * 1024, // 5MB
  extensions: ["jpg", "png", "pdf"],
});

Validate multiple files

import { FileValidator } from "filev";

const result = FileValidator.validateMultiple({
  files: fileList, // File | File[]
  maxSize: 10 * 1024 * 1024, // 10MB
  extensions: ["mp4", "mov"],
});

Validation Rules

You can also use the built-in rules separately:

import { validateSize } from "filev/rules/validate-size";
import { validateType } from "filev/rules/validate-type";
import { validateExtension } from "filev/rules/validate-extension";

validateSize(file, 10 * 1024 * 1024);
validateType(file);
validateExtension(file, ["png", "jpg"]);