SOURCE

{
	console.log('a',`\u0061`);//a a
	console.log('s',`\u20BB7`);//口7 因为超过0xFFFF
	console.log('s',`\u{20BB7}`);//��
}

//返回字符串长度，每两个字节一个长度
{
	let r='a';
	console.log('length',r.length);//1 
	let s='��'
	console.log('length',s.length)//2

	//es5
	console.log('0',s.charAt(0));// 0, �
	console.log('1',s.charAt(1));// 1, �
	console.log('at0',s.charCodeAt(0));//at0, 65533
	console.log('at1',s.charCodeAt(1));//at1, 65533

	//es6
	let s1='��a';//
	console.log('length',s1.length);//3 获取字符长度
	console.log('code0',s1.codePointAt(0));//65533  获取第1个字节的源码
	console.log('code0',s1.codePointAt(0).toString(16));//fffd  获取第1个字节的16进制码
	console.log('code1',s1.codePointAt(1));//65533  获取第2个字节的16进制码
	console.log('code2',s1.codePointAt(2));//97  获取第3个字节的16进制码
}
//从码值变为字符
{
  //es5方法
  console.log(String.fromCharCode("0x20bb7"));//ஷ
  //es6方法
  console.log(String.fromCodePoint("0x20bb7"));//��
}

{
  //es5方法
  let str='\u{20bb7}abc';
  for (let i=0;i<str.length;i++){
    console.log('es5',str[i]);//�,�,a,b,c
  }
  //es6方法
  for (let code of str){
    console.log('es6',code);//��,a,b,c
  }
}

{
  //判断是否包含字符
  let str='string';
  console.log('includes',str.includes("s"));//true
  console.log('includes',str.includes("f"));//false
  //判断字符开始
  console.log('str',str.startsWith("str"));//true
  console.log('fff',str.startsWith("fff"));//false
  //判断字符结束
  console.log('str',str.endsWith("ing"));//true
  console.log('ggg',str.endsWith("ggg"));//false

}

{
  //复制拼接字符串
  let str='abc';
	console.log(str.repeat(2));//abcabc
}


//字符串套用
{
  let name = 'makchikin';
  let info = 'hello world';
  let m =`I am ${name},${info}`;
  console.log(m);//I am makchikin,hello world
}

//自动补白
{
  console.log('1'.padStart(3,'0'));//001
  console.log('1'.padEnd(4,'0'));//1000
}

//标签模板
{
  let user={
    name:'makchikin',
    info:'hello workd'
  };
  console.log(abc `I am ${user.name},${user.info}!`);//I am ,,,!, makchikin, hello workd
  function abc(s,v1,v2){
    console.log(s,v1,v2);//I am ,,,!makchikinhello workd
    return s+v1+v2;
  }
}
//忽略转义字符
{
  console.log(String.raw`hi\n${1+2}`);//hi\n3
  console.log(`hi\n${1+2}`);//hi(换行了)
	//3(换行了)
}