From 9d0455618c13ff7afffe99f859f8a283b229476b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=9D=A8=E5=87=8C=E7=BF=94?= <963304364@qq.com> Date: Thu, 27 Oct 2022 05:38:53 +0000 Subject: [PATCH 1/2] =?UTF-8?q?add=2022=20=E6=9D=A8=E5=87=8C=E7=BF=94/?= =?UTF-8?q?=E7=AC=AC=E4=B8=83=E6=AC=A1=E4=BD=9C=E4=B8=9A/=E7=AC=94?= =?UTF-8?q?=E8=AE=B0.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: 杨凌翔 <963304364@qq.com> --- .../2022-10-26-\345\214\205\350\243\205\347\261\273.md" | 0 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 "22 \346\235\250\345\207\214\347\277\224/\347\254\254\344\270\203\346\254\241\344\275\234\344\270\232/\347\254\224\350\256\260/2022-10-26-\345\214\205\350\243\205\347\261\273.md" diff --git "a/22 \346\235\250\345\207\214\347\277\224/\347\254\254\344\270\203\346\254\241\344\275\234\344\270\232/\347\254\224\350\256\260/2022-10-26-\345\214\205\350\243\205\347\261\273.md" "b/22 \346\235\250\345\207\214\347\277\224/\347\254\254\344\270\203\346\254\241\344\275\234\344\270\232/\347\254\224\350\256\260/2022-10-26-\345\214\205\350\243\205\347\261\273.md" new file mode 100644 index 0000000..e69de29 -- Gitee From fc24e7872e1e04e75310a155de3bb0157e066395 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=9D=A8=E5=87=8C=E7=BF=94?= <963304364@qq.com> Date: Thu, 27 Oct 2022 05:39:07 +0000 Subject: [PATCH 2/2] =?UTF-8?q?update=2022=20=E6=9D=A8=E5=87=8C=E7=BF=94/?= =?UTF-8?q?=E7=AC=AC=E4=B8=83=E6=AC=A1=E4=BD=9C=E4=B8=9A/=E7=AC=94?= =?UTF-8?q?=E8=AE=B0/2022-10-26-=E5=8C=85=E8=A3=85=E7=B1=BB.md.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: 杨凌翔 <963304364@qq.com> --- ...6-\345\214\205\350\243\205\347\261\273.md" | 100 ++++++++++++++++++ 1 file changed, 100 insertions(+) diff --git "a/22 \346\235\250\345\207\214\347\277\224/\347\254\254\344\270\203\346\254\241\344\275\234\344\270\232/\347\254\224\350\256\260/2022-10-26-\345\214\205\350\243\205\347\261\273.md" "b/22 \346\235\250\345\207\214\347\277\224/\347\254\254\344\270\203\346\254\241\344\275\234\344\270\232/\347\254\224\350\256\260/2022-10-26-\345\214\205\350\243\205\347\261\273.md" index e69de29..960fdc5 100644 --- "a/22 \346\235\250\345\207\214\347\277\224/\347\254\254\344\270\203\346\254\241\344\275\234\344\270\232/\347\254\224\350\256\260/2022-10-26-\345\214\205\350\243\205\347\261\273.md" +++ "b/22 \346\235\250\345\207\214\347\277\224/\347\254\254\344\270\203\346\254\241\344\275\234\344\270\232/\347\254\224\350\256\260/2022-10-26-\345\214\205\350\243\205\347\261\273.md" @@ -0,0 +1,100 @@ + + + //keys,values,entries,obj + + var obj = { + name: '李华', + age: 17, + gender: '男' + + } + //for ... of :遍历 + for (e of Object.keys(obj)) { + console.log(e); + } + //将键值对成对变成数组放入外层数组(二维数组) + const arr = Object.entries(obj) + console.log(arr); + for(e of Object.entries(obj)){ + console.log(e); + } + + //obj本身是不可迭代的对象 + for(e of obj){ + console.log(e); + } + + assign:拷贝，浅拷贝(复制的是对象的地址),(手写一个对象的深拷贝)深拷贝(复制的的对象本身) + var obj = { + name: '李华', + age: 16, + gender: '男' + } + var obj1 = { + name: '李四', + title: 'student' + } + var obj2 = { + name:'王五' + } + var obj3 = { + name:'张三' + } + var obj2 = Object.assign(obj); + + age gender name title + assign：1.浅拷贝一个对象 2.合并对象(target,sources....) + console.log(Object.assign(obj,obj1,obj2,4,false,null,[12,3,34],{name:'张三'})); + console.log(obj[0]); + + + 包装类 + 原始数据类型： number, boolean, string, null, undefined (symbol,bigint) + var num = new Number(5) //对象 + num.a = 6 + num = num * 2 //会自动变成原始数据类型number + + var bol = new Boolean(); + bol.a = false + + var str = new String('abc'); + str.a = 'hi' + + 包装类只有：number，boolean，string, + null,undefined是没有包装类的 + + var num = 5; //原始数据类型 + num.a = 7; //1. new Number(5).a = 7 2. delete new Number(5) + console.log(num.a); //new Number(5).a undefined + + const arr = [1,3,4,5] //切片 slice + arr.length = 2 + console.log(arr); + + var str = '1345' //原始数据类型 + str.length = 2 //1.new String('1345').length = 2 2.delete String('1345') + str.aaa = 'a' //new Sting('1345').aaa = a 2.delete String('1345') + console.log(str); + console.log(str.length);//new String('1345').length = 4 + console.log(String.prototype); //String类有很多方法和length + console.log(str.aaa); //new String('1345') + + + console.log('------'); + var num = 50 + num.length = 1 + console.log(num.length); + console.log(Number.prototype); + + //null undefined 没有包装 + + + + + 总结 合并对象 + var target = {name:'李华'} + var obj = {name:'王五'} + console.log(Object.assign(2,obj)); //number + console.log(Object.assign(false,target)); //boolean + //包装类：自动转成对象 + console.log(Object.assign(undefined,obj)); //null undefined -- Gitee