@wollybeard/kit

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Value ​

General value utilities for common JavaScript values and patterns.

Provides utilities for lazy values, type guards for symbols and dates, identity proxies, and lazy value resolution. Includes helpers for working with deferred computations and value type checking.

Import ​

typescript
import { Value } from '@wollybeard/kit'
typescript
import * as Value from '@wollybeard/kit/value'

Lazy Values ​

[T] Lazy ​

typescript
type Lazy<$Value> = () => $Value
Source

A lazy value that is computed when called.

$Value

  • The type of value that will be returned when the lazy function is invoked

[F] lazy ​

typescript
<value>(value: value): Lazy<value>
Source

Parameters:

  • value - The value to wrap in a lazy computation

Returns: A function that returns the wrapped value when called

Creates a lazy value that returns the given value when invoked.

value

  • The type of the value to be lazily returned

Examples:

typescript
const 
lazy
Number
 = 
Value
.lazy(42)

console
.
log
(
lazyNumber
()) // 42

const 
lazy
Object
 = 
Value
.lazy({ 
foo
: 'bar' })

console
.
log
(
lazyObject
()) // { foo: 'bar' }

[U] LazyMaybe ​

typescript
type LazyMaybe<$Value = unknown> = $Value | Lazy<$Value>
Source

A value that may be either immediate or lazy.

$Value

  • The type of the value, whether immediate or lazy

[T] resolveLazy ​

typescript
type resolveLazy<$LazyMaybeValue extends LazyMaybe<any>> =
  $LazyMaybeValue extends Lazy<infer __value__> ? __value__ : $LazyMaybeValue
Source

Type-level resolution of a LazyMaybe value. Extracts the underlying value type whether it's lazy or immediate.

$LazyMaybeValue

  • A value that may be lazy or immediate

[F] resolveLazy ​

typescript
<lazyMaybeValue extends LazyMaybe>(lazyMaybeValue: lazyMaybeValue): resolveLazy<lazyMaybeValue>
Source

Parameters:

  • lazyMaybeValue - A value that may be lazy (function) or immediate

Returns: The resolved value

Resolves a value that may be lazy or immediate. If the value is a function (lazy), it calls it to get the result. If the value is immediate, it returns it as-is.

lazyMaybeValue

  • The type of the potentially lazy value

Examples:

typescript
console
.
log
(
Value
.resolveLazy(42)) // 42

console
.
log
(
Value
.resolveLazy(() => 42)) // 42

const 
lazyConfig
 = () => ({ 
port
: 3000 })

console
.
log
(
Value
.resolveLazy(
lazyConfig
)) // { port: 3000 }

[F] resolveLazyFactory ​

typescript
<value>(lazyMaybeValue: LazyMaybe<value>): () => value
Source

Parameters:

  • lazyMaybeValue - A value that may be lazy (function) or immediate

Returns: A function that when called, resolves and returns the value

Creates a factory function that resolves a lazy or immediate value when called. This is useful when you want to defer the resolution of a LazyMaybe value.

value

  • The type of the value to be resolved

Examples:

typescript
const 
getValue
 = 
Value
.resolveLazyFactory(42)

console
.
log
(
getValue
()) // 42

const 
getLazyValue
 = 
Value
.resolveLazyFactory(() => 42)

console
.
log
(
getLazyValue
()) // 42

// Useful for configuration that may be lazy
const 
getConfig
 = 
Value
.resolveLazyFactory(() => ({
  
apiUrl
: 'https://api.example.com',
}))

console
.
log
(
getConfig
()) // { apiUrl: 'https://api.example.com' }

Type Guards ​

[F] isSymbol ​

typescript
(value: unknown): boolean
Source

Parameters:

  • value - The value to check

Returns: True if the value is a symbol

Type guard to check if a value is a symbol.

Examples:

typescript
Value
.isSymbol(
Symbol
('test')) // true

Value
.isSymbol('test') // false

[F] isDate ​

typescript
(value: unknown): boolean
Source

Parameters:

  • value - The value to check

Returns: True if the value is a Date

Type guard to check if a value is a Date instance.

Examples:

typescript
Value
.isDate(new 
Date
()) // true

Value
.isDate('2024-01-01') // false

Value
.isDate(
Date
.
now
()) // false

Utilities ​

[C] identityProxy ​

typescript
{}
Source

A proxy that returns itself for any property access. Useful for default values or chaining patterns.

Examples:

typescript
Value
.identityProxy.foo.bar.baz // Returns identityProxy

Value
.identityProxy.anything() // Returns identityProxy