ES6字符串相关扩展
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变量的解构赋值
// 数组的解构赋值 let [a,b,c] = [1,2,3]; //1,2,3 let [a,b,c] = [,123,]; //undefined 123 undefined let [a=111,b,c] = [,123,]; //111 123 undefined console.log(a,b,c);
对象的解构赋值
let {foo,bar} = {foo : ‘hello‘,bar : ‘hi‘};//hello hi let {foo,bar} = {bar : ‘hi‘,foo : ‘hello‘};//hello hi console.log(foo,bar); ===================== let {cos,sin,random} = Math; console.log(typeof cos);//function console.log(typeof sin);//function console.log(typeof random);//function
对象属性别名(如果有了别名,那么原来的名字就无效了)
let {foo,bar} = {bar : ‘hi‘,foo : ‘nihao‘}; console.log(foo,bar) //nihao hi ================================================================ let {foo:abc,bar} = {bar : ‘hi‘,foo : ‘nihao‘}; console.log(abc,bar)//nihao hi console.log(foo,bar); // foo is not defined
对象的解构赋值指定默认值
let {foo:abc=‘hello‘,bar} = {bar : ‘hi‘}; console.log(abc,bar);//hello hi
字符串的解构赋值
let [a,b,c,d,e,length] = "hello"; console.log(a,b,c,d,e);//h e l l o console.log(length);// undefined let {length} = "hi"; console.log(length);//2
/* 字符串相关扩展 includes() 判断字符串中是否包含指定的字串(有的话返回true,否则返回false) 参数一:匹配的字串;参数二:从第几个开始匹配 startsWith() 判断字符串是否以特定的字串开始 endsWith() 判断字符串是否以特定的字串结束 模板字符串 */ console.log(‘hello world‘.includes(‘world‘,7));//false console.log(‘hello world‘.includes(‘world‘,6));//true let url = ‘admin/login.html‘; console.log(url.startsWith(‘admin‘));//true console.log(url.endsWith(‘html‘));//true 反引号表示模板,模板中的内容可以有格式,通过${}方式填充数据 let obj = { username : ‘lisi‘, age : ‘12‘, gender : ‘male‘ } let fn = function(info){ return info; } let tpl = ` <div> <span>${obj.username}</span> <span>${obj.age}</span> <span>${obj.gender}</span> <span>${1+1}</span> <span>${fn(‘nihao‘)}</span> </div> `; console.log(tpl); <div> <span>lisi</span> <span>12</span> <span>male</span> <span>2</span> <span>nihao</span> </div>
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