fp-option-ref

name	fp-option-ref
description	Quick reference for Option type. Use when user needs to handle nullable values, optional data, or wants to avoid null checks.
type	skill
created	2026-02-27T00:00:00.000Z
domain	communication-content
category	documentation
risk	unknown
source	community
tags	["skill","communication-content","documentation","option","ref"]

Option Quick Reference

Option = value that might not exist. Some(value) or None.

When to Use

• You need a quick fp-ts reference for nullable or optional values.
• The task involves eliminating null checks, safe property access, or optional chaining with Option.
• You want a short reference card rather than a full migration guide.

Create

import * as O from 'fp-ts/Option'

O.some(5)              // Some(5)
O.none                 // None
O.fromNullable(x)      // null/undefined → None, else Some(x)
O.fromPredicate(x > 0)(x) // false → None, true → Some(x)

Transform

O.map(fn)              // Transform inner value
O.flatMap(fn)          // Chain Options (fn returns Option)
O.filter(predicate)    // None if predicate false

Extract

O.getOrElse(() => default)  // Get value or default
O.toNullable(opt)           // Back to T | null
O.toUndefined(opt)          // Back to T | undefined
O.match(onNone, onSome)     // Pattern match

Common Patterns

import { pipe } from 'fp-ts/function'
 *  O  


(
  O.(user),
  O.( u.),
  O.( O.(p.)),
  O.( )
)


 *  A  
(
  users,
  A.,  
  O.( u.),
  O.( )
)