use-infer

A lightweight TypeScript utility for automatically inferring proper JavaScript types from string values, designed for processing form data, API responses, and other string-based inputs.

Table of Contents

• Installation
• Core Features
• Usage
  • Basic Usage
  • Advanced Usage
• API Reference
  • infer
  • inferValue
• Examples
• Testing
• Author
• License

Installation

npm install use-infer

Core Features

• 🎯 Automatically converts string values to their proper JavaScript types
• 🔄 Handles nested objects and arrays
• ⚡ Type-safe with full TypeScript support
• 🛡️ Preserves original values when conversion isn't appropriate
• 📦 Zero dependencies (except lodash utilities)

Usage

Basic Usage

import infer from 'use-infer';

// Simple object inference
const input = {
	isActive: 'true',
	count: '42',
	name: 'John'
};

const result = infer(input);
// Result:
// {
//   isActive: true,  // boolean
//   count: 42,       // number
//   name: 'John'     // string
// }

Advanced Usage

import infer from 'use-infer';

// Complex nested structure
const input = {
	user: {
		id: '123',
		settings: {
			notifications: 'true',
			theme: 'dark'
		}
	},
	scores: ['42', '98', '75'],
	active: 'true'
};

const result = infer(input);
// Result:
// {
//   user: {
//     id: 123,
//     settings: {
//       notifications: true,
//       theme: 'dark'
//     }
//   },
//   scores: [42, 98, 75],
//   active: true
// }

API Reference

infer

function infer<T extends OutputValue>(obj: InputValue): T;

Recursively processes an object or array, converting string values to their appropriate types.

Type Definitions

type InputPrimitive = string | number | boolean | null | undefined;
type InputObject = { [key: string]: InputValue };
type InputArray = InputValue[];
type InputValue = InputPrimitive | InputObject | InputArray;

type OutputPrimitive = string | number | boolean | null | undefined;
type OutputObject = { [key: string]: OutputValue };
type OutputArray = OutputValue[];
type OutputValue = OutputPrimitive | OutputObject | OutputArray;

inferValue

function inferValue(value: InputPrimitive): OutputPrimitive;

Processes a single value, converting it to the appropriate type if possible.

Examples

Form Data Processing

import infer from 'use-infer';

const formData = {
	username: 'john_doe',
	age: '25',
	subscribed: 'true',
	preferences: {
		emailNotifications: 'true',
		theme: 'dark',
		refreshRate: '60'
	}
};

const processedData = infer(formData);

API Response Handling

import infer from 'use-infer';

const apiResponse = {
	id: '12345',
	items: ['1', '2', '3'],
	metadata: {
		isValid: 'true',
		count: '42',
		tags: ['tag1', 'tag2']
	}
};

const typedResponse = infer(apiResponse);

Testing

The library includes comprehensive test coverage. Run tests with:

npm test

Test coverage includes:

• Basic type inference
• Nested object handling
• Array processing
• Edge cases
• Type safety

👨‍💻 Author

Felipe Rohde

• Twitter: @felipe_rohde
• Github: @feliperohdee
• Email: [email protected]

License

MIT