iif-ts

🧠 A tiny utility for conditional insertion into arrays and objects using the spread operator. Supports lazy evaluation.

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✨ Features

• ✅ Drop-in use with ...spread
• ✅ Supports arrays (iifArray) and objects (iifObject)
• ✅ Lazy evaluation with functions
• ✅ Zero runtime dependencies
• ✅ Fully typed with TypeScript

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💾 Installation

pnpm add iif-ts
# or
npm install iif-ts
# or
yarn add iif-ts

🔧 Usage

➤ Arrays: iifArray

import { iifArray } from 'iif-ts'

const arr = [
  'a',
  ...iifArray(true, 'b', 'c')       // ['b', 'c']
]

const lazy = [
  ...iifArray(condition, () => computeHeavyValue())
]

➤ Objects: iifObject

import { iifObject } from 'iif-ts'

const obj = {
  name: 'Islam',
  ...iifObject(true, { role: 'admin' }) // adds "role" if true
}

const safe = {
  ...iifObject(user?.active, () => ({ token: user.token }))
}

📚 API

iifArray<T>(condition: boolean, ...values: (T | (() => T))[]): T[]

• condition – If true, the values are included.
• values – One or more values or lazy functions returning values.
• ✅ Returns an array or empty array.

iifObject<T>(condition: boolean, value: T | (() => T)): Partial<T>

• condition – If true, the object is returned.
• value – An object or a lazy function returning one.
• ✅ Returns an object or {}.

🛠 Example with JSX (React)

{...iifObject(isDev, { 'data-dev': true })}
{...iifArray(showTooltip, 'aria-label')}

🧪 Testing

This package is fully covered by TypeScript type checks. For full runtime tests, add your own test framework like Vitest or Jest.

📄 License

MIT © Islam Yamor

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