ES6学习笔记4 字符串扩展

{
console.log('a','\u0061')
console.log('s','\u20BB7')//0xFFFF 是2个字节，20BB 作为2个字节，7
console.log('s','\u{20BB7}')//用{}包着

}

{
let s='𠮷'
console.log('length',s.length)
console.log('0',s.charAt(0))
console.log('1',s.charAt(1))
console.log('1',s.charCodeAt(0))//码值 只取2个字节
console.log('1',s.charCodeAt(1))

let s1='𠮷a'
console.log('code0',s1.codePointAt(0))//码值 取4个字节
console.log('code0',s1.codePointAt(0).toString(16))
}

{
console.log(String.fromCharCode("0x20bb7"))
console.log(String.fromCodePoint("0x20bb7"))//es6
}

{
let str='\u{20bb7}abc'
for (let i = 0; i < str.length; i++) {
console.log('es5',str[i])
}

for (let code of str) {
console.log('es6',code)

}
}

{
let str="string"
console.log('includes',str.includes("r"))
console.log('match',str.match("r"))
console.log('star',str.startsWith("str"))
console.log('end',str.endsWith("ng"))
}

{
let str="abc"
console.log(str.repeat(2))//重复
}

{
let name="list"
let info="hello world"
let m=`i am ${name},${info}`//字符串模板
console.log(m)
}

{
console.log('1'.padStart(2,'0'))//补白 1补白2位 01
console.log('1'.padEnd(2,'0'))//向后补 10
}

{
let user={
name:'laohan',
info:'你好'
}

//作用 过滤字符串 防止xss攻击 处理多语言模板转换

abc`i am${user.name}${user.info}`//标签模板
console.log(abc`i am${user.name}${user.info}`)
function abc(s,v1,v2) {
console.log(s,v1,v2)
return s+v1+v2
}

// ["i am ", ",", "", raw: Array(3)] "laohan" "你好"
}

{
console.log(String.raw`Hi\n${1+2}`)//将\转译
console.log(`Hi\n${1+2}`)
}