Constants Reference

License NPM Version Open Issues

🔢 Shared constants and aliases to static methods, values and symbols.

Usage

📦 Node

Install @lou.codes/constants as a dependency:

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pnpm add @lou.codes/constants
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# or
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npm install @lou.codes/constants
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# or
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yarn add @lou.codes/constants

Import it and use it:

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import { iterator } from "@lou.codes/constants/Symbol.js";
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console.log(iterator); // {}

🦕 Deno

Import @lou.codes/constants using the npm: prefix, and use it directly:

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import { iterator } from "npm:@lou.codes/constants/Symbol.js";
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console.log(iterator); // {}

🌎 Browser

Import @lou.codes/constants using esm.sh, and use it directly:

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<script type="module">
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	import { iterator } from "https://esm.sh/@lou.codes/constants/Symbol.js";
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	console.log(iterator); // {}
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</script>

Useful links

📝 Documentation: TypeDoc generated documentation.
⏳ Changelog: List of changes between versions.

Array

Functions

from()

from(arrayLike)

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function from<T>(arrayLike: ArrayLike<T>): T[];

Creates an array from an array-like object.

Type parameters

Type parameter
`T`

Parameters

Parameter	Type	Description
`arrayLike`	`ArrayLike`<`T`>	An array-like object to convert to an array.

Returns

T[]

from(arrayLike, mapfn, thisArg)

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function from<T, U>(
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	arrayLike: ArrayLike<T>,
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	mapfn: (v: T, k: number) => U,
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	thisArg?: any,
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): U[];

Creates an array from an iterable object.

Type parameters

Type parameter
`T`
`U`

Parameters

Parameter	Type	Description
`arrayLike`	`ArrayLike`<`T`>	An array-like object to convert to an array.
`mapfn`	(`v`: `T`, `k`: `number`) => `U`	A mapping function to call on every element of the array.
`thisArg`?	`any`	Value of ‘this’ used to invoke the mapfn.

Returns

U[]

from(iterable)

1
function from<T>(iterable: Iterable<T> | ArrayLike<T>): T[];

Creates an array from an iterable object.

Type parameters

Type parameter
`T`

Parameters

Parameter	Type	Description
`iterable`	`Iterable`<`T`> \| `ArrayLike`<`T`>	An iterable object to convert to an array.

Returns

T[]

from(iterable, mapfn, thisArg)

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function from<T, U>(
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	iterable: Iterable<T> | ArrayLike<T>,
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	mapfn: (v: T, k: number) => U,
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	thisArg?: any,
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): U[];

Creates an array from an iterable object.

Type parameters

Type parameter
`T`
`U`

Parameters

Parameter	Type	Description
`iterable`	`Iterable`<`T`> \| `ArrayLike`<`T`>	An iterable object to convert to an array.
`mapfn`	(`v`: `T`, `k`: `number`) => `U`	A mapping function to call on every element of the array.
`thisArg`?	`any`	Value of ‘this’ used to invoke the mapfn.

Returns

U[]

isArray()

1
function isArray(arg: any): arg is any[];

Parameters

Parameter	Type
`arg`	`any`

Returns

arg is any[]

Number

Functions

isFinite()

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function isFinite(number: unknown): boolean;

Returns true if passed value is finite. Unlike the global isFinite, Number.isFinite doesn’t forcibly convert the parameter to a number. Only finite values of the type number, result in true.

Parameters

Parameter	Type	Description
`number`	`unknown`	A numeric value.

Returns

boolean

isNaN()

1
function isNaN(number: unknown): boolean;

Returns a Boolean value that indicates whether a value is the reserved value NaN (not a number). Unlike the global isNaN(), Number.isNaN() doesn’t forcefully convert the parameter to a number. Only values of the type number, that are also NaN, result in true.

Parameters

Parameter	Type	Description
`number`	`unknown`	A numeric value.

Returns

boolean

isSafeInteger()

1
function isSafeInteger(number: unknown): boolean;

Returns true if the value passed is a safe integer.

Parameters

Parameter	Type	Description
`number`	`unknown`	A numeric value.

Returns

boolean

Object

Functions

assign()

assign(target, source)

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function assign<T, U>(target: T, source: U): T & U;

Copy the values of all of the enumerable own properties from one or more source objects to a target object. Returns the target object.

Type parameters

Type parameter
`T` extends `object`
`U`

Parameters

Parameter	Type	Description
`target`	`T`	The target object to copy to.
`source`	`U`	The source object from which to copy properties.

Returns

T & U

assign(target, source1, source2)

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function assign<T, U, V>(target: T, source1: U, source2: V): T & U & V;

Copy the values of all of the enumerable own properties from one or more source objects to a target object. Returns the target object.

Type parameters

Type parameter
`T` extends `object`
`U`
`V`

Parameters

Parameter	Type	Description
`target`	`T`	The target object to copy to.
`source1`	`U`	The first source object from which to copy properties.
`source2`	`V`	The second source object from which to copy properties.

Returns

T & U & V

assign(target, source1, source2, source3)

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function assign<T, U, V, W>(
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	target: T,
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	source1: U,
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	source2: V,
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	source3: W,
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): T & U & V & W;

Copy the values of all of the enumerable own properties from one or more source objects to a target object. Returns the target object.

Type parameters

Type parameter
`T` extends `object`
`U`
`V`
`W`

Parameters

Parameter	Type	Description
`target`	`T`	The target object to copy to.
`source1`	`U`	The first source object from which to copy properties.
`source2`	`V`	The second source object from which to copy properties.
`source3`	`W`	The third source object from which to copy properties.

Returns

T & U & V & W

assign(target, sources)

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function assign(target: object, ...sources: any[]): any;

Copy the values of all of the enumerable own properties from one or more source objects to a target object. Returns the target object.

Parameters

Parameter	Type	Description
`target`	`object`	The target object to copy to.
…`sources`	`any`[]	One or more source objects from which to copy properties

Returns

any

create()

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function create<OutputType>(object?: OutputType): OutputType;

Alias for Object.create(null) combined with Object.assign to create an object without prototype.

Type parameters

Type parameter	Value
`OutputType`	`object`

Parameters

Parameter	Type
`object`?	`OutputType`

Returns

OutputType

Object with no prototype.

See

defineProperty()

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function defineProperty<T>(
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	o: T,
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	p: PropertyKey,
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	attributes: PropertyDescriptor & ThisType<any>,
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): T;

Adds a property to an object, or modifies attributes of an existing property.

Type parameters

Type parameter
`T`

Parameters

Parameter	Type	Description
`o`	`T`	Object on which to add or modify the property. This can be a native JavaScript object (that is, a user-defined object or a built in object) or a DOM object.
`p`	`PropertyKey`	The property name.
`attributes`	`PropertyDescriptor` & `ThisType`<`any`>	Descriptor for the property. It can be for a data property or an accessor property.

Returns

T

entries()

entries(o)

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function entries<T>(o: object | ArrayLike<T>): [string, T][];

Returns an array of key/values of the enumerable properties of an object

Type parameters

Type parameter
`T`

Parameters

Parameter	Type	Description
`o`	`object` \| `ArrayLike`<`T`>	Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns

[string, T][]

entries(o)

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function entries(o: object): [string, any][];

Returns an array of key/values of the enumerable properties of an object

Parameters

Parameter	Type	Description
`o`	`object`	Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns

[string, any][]

freeze()

freeze(f)

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function freeze<T>(f: T): T;

Prevents the modification of existing property attributes and values, and prevents the addition of new properties.

Type parameters

Type parameter
`T` extends `Function`

Parameters

Parameter	Type	Description
`f`	`T`	Object on which to lock the attributes.

Returns

T

freeze(o)

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function freeze<T, U>(o: T): Readonly<T>;

Prevents the modification of existing property attributes and values, and prevents the addition of new properties.

Type parameters

Type parameter
`T` extends `object`

Parameters

Parameter	Type	Description
`o`	`T`	Object on which to lock the attributes.

Returns

Readonly<T>

freeze(o)

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function freeze<T>(o: T): Readonly<T>;

Prevents the modification of existing property attributes and values, and prevents the addition of new properties.

Type parameters

Type parameter
`T`

Parameters

Parameter	Type	Description
`o`	`T`	Object on which to lock the attributes.

Returns

Readonly<T>

fromEntries()

fromEntries(entries)

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function fromEntries<T>(entries: Iterable<readonly [PropertyKey, T]>): object;

Returns an object created by key-value entries for properties and methods

Type parameters

Type parameter	Value
`T`	`any`

Parameters

Parameter	Type	Description
`entries`	`Iterable`<readonly [`PropertyKey`, `T`]>	An iterable object that contains key-value entries for properties and methods.

Returns

object

fromEntries(entries)

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function fromEntries(entries: Iterable<readonly any[]>): any;

Returns an object created by key-value entries for properties and methods

Parameters

Parameter	Type	Description
`entries`	`Iterable`<readonly `any`[]>	An iterable object that contains key-value entries for properties and methods.

Returns

any

getOwnPropertyDescriptor()

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function getOwnPropertyDescriptor(
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	o: any,
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	p: PropertyKey,
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): undefined | PropertyDescriptor;

Gets the own property descriptor of the specified object. An own property descriptor is one that is defined directly on the object and is not inherited from the object’s prototype.

Parameters

Parameter	Type	Description
`o`	`any`	Object that contains the property.
`p`	`PropertyKey`	Name of the property.

Returns

undefined | PropertyDescriptor

getPrototypeOf()

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function getPrototypeOf(o: any): any;

Returns the prototype of an object.

Parameters

Parameter	Type	Description
`o`	`any`	The object that references the prototype.

Returns

any

hasOwn()

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function hasOwn(o: object, v: PropertyKey): boolean;

Determines whether an object has a property with the specified name.

Parameters

Parameter	Type	Description
`o`	`object`	An object.
`v`	`PropertyKey`	A property name.

Returns

boolean

is()

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function is(value1: any, value2: any): boolean;

Returns true if the values are the same value, false otherwise.

Parameters

Parameter	Type	Description
`value1`	`any`	The first value.
`value2`	`any`	The second value.

Returns

boolean

keys()

keys(o)

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function keys(o: object): string[];

Returns the names of the enumerable string properties and methods of an object.

Parameters

Parameter	Type	Description
`o`	`object`	Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns

string[]

keys(o)

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function keys(o: object): string[];

Returns the names of the enumerable string properties and methods of an object.

Parameters

Parameter	Type	Description
`o`	`object`	Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns

string[]

values()

values(o)

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function values<T>(o: object | ArrayLike<T>): T[];

Returns an array of values of the enumerable properties of an object

Type parameters

Type parameter
`T`

Parameters

Parameter	Type	Description
`o`	`object` \| `ArrayLike`<`T`>	Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns

T[]

values(o)

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function values(o: object): any[];

Returns an array of values of the enumerable properties of an object

Parameters

Parameter	Type	Description
`o`	`object`	Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns

any[]

Reflect

Functions

ownKeys()

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function ownKeys(target: object): (string | symbol)[];

Returns the string and symbol keys of the own properties of an object. The own properties of an object are those that are defined directly on that object, and are not inherited from the object’s prototype.

Parameters

Parameter	Type	Description
`target`	`object`	Object that contains the own properties.

Returns

(string | symbol)[]

String

Functions

raw()

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function raw(template: object, ...substitutions: any[]): string;

String.raw is usually used as a tag function of a Tagged Template String. When called as such, the first argument will be a well formed template call site object and the rest parameter will contain the substitution values. It can also be called directly, for example, to interleave strings and values from your own tag function, and in this case the only thing it needs from the first argument is the raw property.

Parameters

Parameter	Type	Description
`template`	`object`	A well-formed template string call site representation.
`template.raw`	readonly `string`[] \| `ArrayLike`<`string`>	-
…`substitutions`	`any`[]	A set of substitution values.

Returns

string

Symbol

Variables

asyncIterator

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const asyncIterator: typeof Symbol.asyncIterator = SymbolAlias.asyncIterator;

Alias for Symbol.asyncIterator.

See

Symbol.asyncIterator

iterator

1
const iterator: typeof Symbol.iterator = SymbolAlias.iterator;

Alias for Symbol.iterator.

See

Symbol.iterator

empty

Variables

EMPTY_ARRAY

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const EMPTY_ARRAY: readonly [];

Empty read only array.

EMPTY_OBJECT

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const EMPTY_OBJECT: Readonly<object>;

Empty readonly object.

EMPTY_STRING

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const EMPTY_STRING: "" = "";

Empty string.