Function Object

Readonly prototype

assign

• assign<T, U>(target, source): 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

  • T extends {}

  • U

  Parameters

  • target: T

    The target object to copy to.

  • source: U

    The source object from which to copy properties.

  Returns T & U
• assign<T, U, V>(target, source1, source2): 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

  • T extends {}

  • U

  • V

  Parameters

  • 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<T, U, V, W>(target, source1, source2, source3): 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

  • T extends {}

  • U

  • V

  • W

  Parameters

  • 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): 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

  • target: object

    The target object to copy to.

  • Rest ...sources: any[]

    One or more source objects from which to copy properties

  Returns any

create

• create(o): any

• Creates an object that has the specified prototype or that has null prototype.

  Parameters

  • o: null | object

    Object to use as a prototype. May be null.

  Returns any
• create(o, properties): any

• Creates an object that has the specified prototype, and that optionally contains specified properties.

  Parameters

  • o: null | object

    Object to use as a prototype. May be null

  • properties: PropertyDescriptorMap & ThisType<any>

    JavaScript object that contains one or more property descriptors.

  Returns any

defineProperties

• defineProperties<T>(o, properties): T

• Adds one or more properties to an object, and/or modifies attributes of existing properties.

  Type Parameters

  • T

  Parameters

  • o: T

    Object on which to add or modify the properties. This can be a native JavaScript object or a DOM object.

  • properties: PropertyDescriptorMap & ThisType<any>

    JavaScript object that contains one or more descriptor objects. Each descriptor object describes a data property or an accessor property.

  Returns T

defineProperty

• defineProperty<T>(o, p, attributes): T

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

  Type Parameters

  • T

  Parameters

  • 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<T>(o): [string, T][]

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

  Type Parameters

  • T

  Parameters

  • o: {
        [s: string]: T;
    } | 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): [string, any][]

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

  Parameters

  • o: {}

    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<T>(f): T

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

  Type Parameters

  • T extends Function

  Parameters

  • f: T

    Object on which to lock the attributes.

  Returns T
• freeze<T, U>(o): Readonly<T>

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

  Type Parameters

  • T extends {
        [idx: string]: U | null | undefined | object;
    }

  • U extends string | number | bigint | boolean | symbol

  Parameters

  • o: T

    Object on which to lock the attributes.

  Returns Readonly<T>
• freeze<T>(o): Readonly<T>

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

  Type Parameters

  • T

  Parameters

  • o: T

    Object on which to lock the attributes.

  Returns Readonly<T>

fromEntries

• fromEntries<T>(entries): {
      [k: string]: T;
  }

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

  Type Parameters

  • T = any

  Parameters

  • entries: Iterable<readonly [PropertyKey, T]>

    An iterable object that contains key-value entries for properties and methods.

  Returns {
      [k: string]: T;
  }

  • [k: string]: T
• fromEntries(entries): any

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

  Parameters

  • entries: Iterable<readonly any[]>

    An iterable object that contains key-value entries for properties and methods.

  Returns any

getOwnPropertyDescriptor

• getOwnPropertyDescriptor(o, p): 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

  • o: any

    Object that contains the property.

  • p: PropertyKey

    Name of the property.

  Returns undefined | PropertyDescriptor

getOwnPropertyDescriptors

• getOwnPropertyDescriptors<T>(o): {
      [P in string | number | symbol]: TypedPropertyDescriptor<T[P]>
  } & {
      [x: string]: PropertyDescriptor;
  }

• Returns an object containing all own property descriptors of an object

  Type Parameters

  • T

  Parameters

  • o: 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 {
      [P in string | number | symbol]: TypedPropertyDescriptor<T[P]>
  } & {
      [x: string]: PropertyDescriptor;
  }

getOwnPropertyNames

• getOwnPropertyNames(o): string[]

• Returns the names 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. The properties of an object include both fields (objects) and functions.

  Parameters

  • o: any

    Object that contains the own properties.

  Returns string[]

getOwnPropertySymbols

• getOwnPropertySymbols(o): symbol[]

• Returns an array of all symbol properties found directly on object o.

  Parameters

  • o: any

    Object to retrieve the symbols from.

  Returns symbol[]

getPrototypeOf

• getPrototypeOf(o): any

• Returns the prototype of an object.

  Parameters

  • o: any

    The object that references the prototype.

  Returns any

is

• is(value1, value2): boolean

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

  Parameters

  • value1: any

    The first value.

  • value2: any

    The second value.

  Returns boolean

isExtensible

• isExtensible(o): boolean

• Returns a value that indicates whether new properties can be added to an object.

  Parameters

  • o: any

    Object to test.

  Returns boolean

isFrozen

• isFrozen(o): boolean

• Returns true if existing property attributes and values cannot be modified in an object, and new properties cannot be added to the object.

  Parameters

  • o: any

    Object to test.

  Returns boolean

isSealed

• isSealed(o): boolean

• Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.

  Parameters

  • o: any

    Object to test.

  Returns boolean

keys

• keys(o): string[]

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

  Parameters

  • 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): string[]

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

  Parameters

  • o: {}

    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[]

preventExtensions

• preventExtensions<T>(o): T

• Prevents the addition of new properties to an object.

  Type Parameters

  • T

  Parameters

  • o: T

    Object to make non-extensible.

  Returns T

seal

• seal<T>(o): T

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

  Type Parameters

  • T

  Parameters

  • o: T

    Object on which to lock the attributes.

  Returns T

setPrototypeOf

• setPrototypeOf(o, proto): any

• Sets the prototype of a specified object o to object proto or null. Returns the object o.

  Parameters

  • o: any

    The object to change its prototype.

  • proto: null | object

    The value of the new prototype or null.

  Returns any

values

• values<T>(o): T[]

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

  Type Parameters

  • T

  Parameters

  • o: {
        [s: string]: T;
    } | 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): any[]

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

  Parameters

  • o: {}

    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[]