ES2018(ES9)新增东西

ES2018(ES9):
    1. 命名捕获
        语法:  (?<名字>)

        let str = '2018-03-20';
        let reg = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/;
        let {year, month ,day} = str.match(reg).groups;
        console.log(year, month, day);
    反向引用:
        \1  \2     $1  $2
    反向引用命名捕获:
        语法:  \k<名字>

        let reg = /^(?<Strive>welcome)-\k<Strive>$/;

        匹配: ‘welcome-welcome’

        -------------------------------------------------

        let reg = /^(?<Strive>welcome)-\k<Strive>-\1$/;

        匹配: 'welcome-welcome-welcome'

    替换:
        $<名字>

        let reg = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/;
        str = str.replace(reg,'$<day>/$<month>/$<year>');
        console.log(str);

        ----------------------------------------
        str = str.replace(reg, (...args)=>{
            //console.log(args)
            let {year, month, day} = args[args.length-1];

            return `${day}/${month}/${year}`;
        });

        console.log(str);

    2.   dotAll 模式  s

        之前 '.' 在正则里表示匹配任意东西， 但是不包括 \n 
    
       let reg = /\w+/gims;

    3. 标签函数
        function fn(){

        }

        fn()  //这样调用就是普通函数

        fn`aaa`  //标签函数使用

        -----------------------------------
        function fn(args){
            return args[0].toUpperCase();
        }

        console.log(fn`welcome`);

    // let str = '2018-03-20'
    // let reg = /(\d{4})-(\d{2})-(\d{2})/;
    // console.log(str.match(reg))//["2018-03-20", "2018", "03", "20", index: 0, input: "2018-03-20", groups: undefined]
    // let dateArr = str.match(reg)
    // let year = dateArr[1]
    // let month = dateArr[2]
    // let day = dateArr[3]
    // console.log(year, month, day)

    // 命名捕获-- > 语法: (? <名字>)

    // let str = '2018-03-20';
    // let reg = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/;
    // let { year, month, day } = str.match(reg).groups;
    // console.log(year, month, day);

    // 反向引用 \1 \2
    // 反向引用命名捕获:语法:  \k<名字>
    // let reg = /^(?<Strive>welcome)-\k<Strive>$/;
    // let reg = /^(?<Strive>welcome)-\k<Strive>-\1$/;//匹配: 'welcome-welcome-welcome'
    // let str = 'a-a';
    // let str2 = 'Strive-Strive'
    // let str3 = 'welcome-welcome'
    // let str4 = 'welcome-welcome-welcome'
    // console.log(reg.test(str))//false
    // console.log(reg.test(str2))//false
    // console.log(reg.test(str3))//true
    // console.log(reg.test(str4))//false

    // 替换: $<名字>

    // let str = '2018-03-20'//换成20/03/2018
    // let reg = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/;
    // // str = str.replace(reg, '$<year>/$<month>/$<day>')
    // str = str.replace(reg, '$<day>/$<month>/$<year>')
    // console.log(str)

    // let str = '2018-03-20'//换成20/03/2018
    // let reg = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/;
    // str.replace(reg, (...args) => {
    //     let { year, month, day } = args[args.length - 1]
    //     return `${day}/${month}/${year}`
    //     // console.log(args)
    // })
    // console.log(str)

    //     dotAll 模式  s
    // 之前 '.' 在正则里表示匹配任意东西， 但是不包括 \n 
    // let reg = /\w+/gims;

    // let reg = /^\w+.\w+$/;
    let reg = /^\w+.\w+$/s;
    // let str = 'welcome-51mmr'
    // let str = 'welcome]51mmr'
    let str = 'welcome\n51mmr'//false

    console.log(reg.test(str))

 function fn(args) {
        console.log(args)
        return 1
    }
    console.log(fn`welcome`)