for…in…
Object . prototype. fun = ( ) => {
} ;
const obj = {
name : '张三' , age : 18 } ;
for ( const i in obj) {
console. log ( i) ;
}
Object . prototype. fun = ( ) => {
} ;
const obj = {
name : '张三' , age : 18 } ;
for ( const i in obj) {
if ( Object . prototype. hasOwnProperty . call ( obj, i) ) {
console. log ( i, ':' , obj[ i] ) ;
}
}
Object.keys
Object . prototype. fun = ( ) => {
} ;
const str = 'HelloWorld' ;
console. log ( Object. keys ( str) ) ;
const obj = {
name : '张三' , age : 18 } ;
console. log ( Object. keys ( obj) ) ;
Object.values
Object . prototype. fun = ( ) => {
} ;
const str = 'HelloWorld' ;
console. log ( Object. values ( str) ) ;
const obj = {
name : '张三' , age : 18 } ;
console. log ( Object. values ( obj) ) ;
Object.entries
const str = 'hello' ;
for ( const [ key, value] of Object. entries ( str) ) {
console. log ( ` ${
key} : ${
value} ` ) ;
}
const obj = {
name : '张三' , age : 18 } ;
for ( const [ key, value] of Object. entries ( obj) ) {
console. log ( ` ${
key} : ${
value} ` ) ;
}
Object.getOwnPropertyNames
const str = 'hello'
console. log ( Object. getOwnPropertyNames ( str) ) ;
const obj = {
name : '张三' , age : 18 } ;
const symbol1 = Symbol ( 'symbol1' )
const symbol2 = Symbol ( 'symbol2' )
obj[ symbol1] = 'hello'
obj[ symbol2] = 'world'
console. log ( Object. getOwnPropertyNames ( obj) ) ;
Object.getOwnPropertySymbols()
const obj = {
name : '张三' , age : 18 } ;
const symbol1 = Symbol ( 'symbol1' )
const symbol2 = Symbol ( 'symbol2' )
obj[ symbol1] = 'hello'
obj[ symbol2] = 'world'
console. log ( Object. getOwnPropertySymbols ( obj) ) ;
Reflect.ownKeys()
const obj = {
name : '张三' , age : 18 } ;
const symbol1 = Symbol ( 'symbol1' )
const symbol2 = Symbol ( 'symbol2' )
obj[ symbol1] = 'hello'
obj[ symbol2] = 'world'
console. log ( Reflect. ownKeys ( obj) ) ;