Sharing about the commonly used new methods of string in ES6

ES6 adds many new methods to js, ​​including traversal, query, replacement, etc., which can easily replace similar methods in ES5. This article mainly introduces the commonly used new methods of string string in ES6, combined with example forms This article summarizes and analyzes the new methods, functions and usage techniques commonly used in string strings in ES6. Friends in need can refer to it. I hope it can help everyone.

for…of:

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

Because es5 does not have a string-related traversal method for js , for...of will undoubtedly play a very important role in the next front-end development.

includes:

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

string.includes(s,i) method parameter 1 needs to be queried Character (string), parameter 2 is the starting position of the query, returns a Boolean value, and indexOf returns the position of the query.

startsWith：

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

string.startsWith(s,i) method parameter 1 needs to be queried Character (string), parameter 2 is the starting position of the query, and returns a Boolean value, indicating whether the character (string) is located at the head position of the string.

endsWith：

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

string.endsWith() method parameter 1 is the required query character (string ), parameter 2 is the starting position of the query, and returns a Boolean value indicating whether the character (string) is located at the end of the string.

repeat：

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

string.repeat(num) method, the parameter num is a repeated string The number of times, please see the code for the return values ​​in various situations.

${}:

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

During the development process, jq is often used to dynamically add elements To add sub-elements or dynamically add content, in the past we added variables through string concatenation. The addition of ES6 can very well replace the old method of jq. Single quotes plus '${}' can not only embed variables, but also maintain the code format, and js code can be run inside {}.

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Detailed explanation of javaScript string tool class StringUtils

Implementation of converting string to String array in Java Method

JS method to convert string string into json object

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