Conditional Switch 🚦

A flexible and powerful TypeScript utility for conditional rendering and logic, inspired by functional programming patterns. condSwitch allows you to write clean, declarative, and expressive conditional logic, especially in scenarios where traditional if/else or switch statements can be verbose or cumbersome.

Table of Contents

• 🚀 Features
• 📦 Installation
• 💡 Usage
• 🤖 API
• ✨ Use Cases
• 🏆 Best Practices
• 🗺️ Roadmap
• 🤝 Contributing
• 📜 License

🚀 Features

• Declarative Style: Write more readable and maintainable code.
• Lazy Evaluation: Conditions and values can be functions, delaying their execution until needed, which can be a performance boost.
• Type-Safe: Written in TypeScript to ensure type safety.
• Flexible: Supports both object and array-based condition-value pairs.
• Default Value: Provides a fallback default value.

📦 Installation

npm install condition-switch
# or
yarn add condition-switch
# or
pnpm add condition-switch

💡 Usage

Basic Usage

condSwitch takes an array of condition-value pairs and a default value. It returns the value of the first condition that evaluates to true.

1. Array of Objects ({ condition, value })

import condSwitch from 'condition-switch'

const result = condSwitch(
  [
    { condition: false, value: 'Not this one' },
    { condition: true, value: 'This is it!' }
  ],
  'Default value'
)

console.log(result) // "This is it!"

2. Array of Tuples ([condition, value])

import condSwitch from 'condition-switch'

const result = condSwitch(
  [
    [false, 'Not this one'],
    [true, 'This is it!']
  ],
  'Default value'
)

console.log(result) // "This is it!"

⚡️ Lazy Evaluation with Functions

For performance-critical sections, you can use functions for conditions and values. This ensures that they are only executed when necessary.

import condSwitch from 'condition-switch'

const expensiveCalculation = () => {
  console.log('Performing expensive calculation...')
  return 42
}

const result = condSwitch(
  [
    [() => false, 'Not this one'],
    [() => true, expensiveCalculation]
  ],
  'Default value'
)

console.log(result)
// "Performing expensive calculation..."
// 42

🤖 API

condSwitch<T, DefaultT>(conditionWithValues, defaultValue)

• conditionWithValues (ConditionWithValue<T>[]): An array of condition-value pairs.
  • ConditionWithValue<T> can be:
    • { condition: unknown, value: T | (() => T) }
    • [unknown, T | (() => T)]
• defaultValue (DefaultT | (() => DefaultT)): The value to return if no conditions are met. Can also be a function for lazy evaluation.

Type Aliases

• Condition (unknown): Any value that can be evaluated for truthiness.
• Value<T> (T | (() => T)): A value or a function that returns a value.

✨ Use Cases

React

import condSwitch from 'condition-switch'

const MyComponent = ({ isLoading, isError, data }) => {
  return (
    <div>
      {condSwitch(
        [
          { condition: isLoading, value: () => <LoadingSpinner /> },
          { condition: isError, value: () => <ErrorMessage /> },
          { condition: data, value: () => <Content data={data} /> }
        ],
        () => (
          <NoDataMessage />
        )
      )}
    </div>
  )
}

Vanilla JavaScript

import condSwitch from 'condition-switch'

const getGreeting = (hour) => {
  return condSwitch(
    [
      [hour < 12, 'Good morning'],
      [hour < 18, 'Good afternoon']
    ],
    'Good evening'
  )
}

console.log(getGreeting(10)) // "Good morning"

🏆 Best Practices

• Use functions for expensive operations: For values that are computationally expensive to generate, use a function to delay the execution until the condition is met.
• Keep conditions simple: For readability, it's best to keep the conditions as simple as possible. If you have complex logic, consider extracting it into a separate function.
• Use the object format for clarity: When you have many conditions, using the { condition, value } format can make your code more self-documenting.

🗺️ Roadmap

• [ ] Add support for more complex conditions (e.g., pattern matching).
• [ ] Explore optimizations for performance.
• [ ] Add more examples and use cases to the documentation.

🤝 Contributing

Contributions, issues, and feature requests are welcome! Feel free to check the issues page.

📜 License

This project is MIT licensed.