ES6中字符串string常用的新增方法小结

let str="wbiokr";
for(let s of str){
  console.log(s)
}
//结果：w, b, i, o, k, r

let str="wbiokr";
str.includes('wb');//结果:true
str.includes('wbiokr');//结果：true
str.includes('w',1);//false
str.includes('b',1);//true

let str="wbiokr";
str.startsWith('wb');//结果:true
str.startsWith('w');//结果:true
str.startsWith('w',1);//结果:false
str.startsWith('b',1);//true
str.startsWith('kr');//结果：false

let str="wbiokr";
str.endsWith('kr');//结果:true
str.endsWith('r');//结果:true
str.endsWith('wb');//结果：false
str.endsWith('i',6);//false
str.endsWith('i',3);//false
str.endsWith('kr',6);//true

let str="wbiokr";
str.repeat(2);//wbiokrwbiokr"str被重复了2次返回，str不改变
'hi'.repeat(3);//"hihihi"
'hi'.repeat(2.6);//'hihi'浮点类型参数，会取整重复
'hi'.repeat(0);//''0的时候返回空字符串
'hi'.repeat(-3)//负数，报错
'hi'.repeat(undefined)//''undefined转化为0
'hi'.repeat(null)//''null转化为0
'hi'.repeat(NaN)//''NaN转化为0

let str="wbiokr";
$('#box').html('
  there is a word ${str},i know it
');
//there is a word wbiokr,i know it