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Object.entries()
2022-08-02 12:34:00 【m0_67394006】
Object.entries() method returns an array of key-value pairs for the given object's own enumerable properties.
The order is the same as that returned when looping over the object using for...in
(the difference being that the for-in loop also enumerates properties in the prototype chain).
Syntax
Object.entries(obj)
Parameters
obj: An object that can return key-value pairs of its enumerable properties.
Return value
An array of key-value pairs for the given object's own enumerable properties.
Description
Object.entries()
returns an array whose elements are the arrays corresponding to the key-value pairs of enumerable properties found directly on object
.The properties are in the same order as given by manually looping through the object's property values.
The parameter is an object
const obj = { name: 'xiaoming', age: 'seven',sex: 'man', grade: 'four' };const res = Object.entries(obj)console.log(res);
Run result:
The parameter is an array
const obj = [1,2,3,4,5,6]const res = Object.entries(obj)console.log(res);
Run result:
The parameter is an array (the array contains objects)
const obj = [1,2,3,4,5,6,{a:'a'},{b:'b'},{c:'c'}]const res = Object.entries(obj)console.log(res);
Run result:
The parameter is an array (the elements in the array are objects)
const obj = [{a:'a'},{b:'b'},{c:'c'}]const res = Object.entries(obj)console.log(res);
Run result:
Objectconverted to
Map
The
new Map()
constructor accepts an iterable ofentries
.With the help of theObject.entries
method you can easily convertObject
toMap
.
const obj = { name: 'xiaoming', age: 'seven',sex: 'man', grade: 'four' };console.log(Object.entries(obj));const map = new Map(Object.entries(obj));console.log(map);
Run result:
Summary
Object.entries() can traverse the key value of an object in the form of an array. The result is the same as the result returned when for...in
loops through the object, but it will not traverseits prototype properties.
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