nanoption

Tiny (220 bytes), zero dependency wrapper for nullable values.

TL;RD

// Without nanoption
const parsedInput = nullableVar != null
  ? parseInt(nullableVar) + 12
  : 1

calculate(parsedInput)

// With nanoption
import { Option } from 'nanoption'

const parsedInput = Option.of(nullableVar)
  .map(v => parseInt(v))
  .map(v => v + 12)
  .getOrElse(1)

calculate(parsedInput)

Installation

yarn add nanoption

Or if you prefer npm:

npm i nanoption

Motivation

It JS in some cases we can get an error Cannot do something of undefined/null. This library explicitly works with nullable values and provide clear interface for it.

Also, library support TypeSciript as first-class citizen and do some checks in complie time. For example:

import { Option } from 'nanoption'

// #map
Option.of(2).map(_ => _ * 2) // Some(4)
Option.of().map(() => 2)     // None (known at compile time)

// #get
Option.of(3).get()           // 3
Option.of().get()            // COMPILE ERROR! Can't call get() on None

Of course, you can use JavaScript without TypeScript, but it's not as fun.

Now Optional Chaining Proposal only on stage 1, but very useful. This library give ECMAScript-version independent alternative for it.

API

import { Option } from 'nanoption'

// Create an option
Option.of(3)                                // Some(3)
Option.of('abc')                            // Some('abc')
Option.of(null)                             // None
Option.of(undefined)                        // None

// #map
Option.of(2).map(_ => _ * 2)                // Some(4)
Option.of().map(() => 2)                    // None

// #flatMap
Option.of(3).flatMap(_ => Option.of(_ * 2)) // Some(6)
Option.of().flatMap(() => Option.of(2))     // None

// #get
Option.of(3).get()                          // 3
Option.of().get()                           // throw Exception

// #getOrElse
Option.of(1).getOrElse(2)                   // 1
Option.of(null).getOrElse(2)                // 2

// #isEmpty
Option.of(2).isEmpty()                      // false
Option.of().isEmpty()                       // true

// #nonEmpty
Option.of(2).nonEmpty()                     // true
Option.of().nonEmpty()                      // false

// #toString
Option.of(2).toString()                     // "Some(2)"
Option.of().toString()                      // "None"

Alternatives

• tsoption is Fantasyland-compliant, but it requires 2-3 times more space.