267 String extension method: template string (resolve the variable, line feed, call the function), startsWith (), endsWith (), repeat ()

Template string (★★★)

ES6 create a string of new ways to use the definition of anti-quotes

let name = `zhangsan`;

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Templates can parse the string variable

let name = '张三'; 
let sayHello = `hello,my name is ${name}`; // hello, my name is zhangsan

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Template string can wrap

 let result = { 
     name: 'zhangsan', 
     age: 20,
     sex: '男' 
 } 
 let html = ` <div>
     <span>${result.name}</span>
     <span>${result.age}</span>
     <span>${result.sex}</span>
 </div> `;

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In the template string can call the function

const sayHello = function () { 
    return '哈哈哈哈 追不到我吧 我就是这么强大';
 }; 
 let greet = `${sayHello()} 哈哈哈哈`;
 console.log(greet); // 哈哈哈哈 追不到我吧 我就是这么强大 哈哈哈哈

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Examples of the method: startsWith () and endsWith ()

• startsWith (): whether the parameter string representing the head of the string, returns a Boolean value
• endsWith (): a parameter indicating whether the string at the end of the string, returns a Boolean value

let str = 'Hello world!';
str.startsWith('Hello') // true 
str.endsWith('!')       // true

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Examples of the method: repeat ()

The method represents a repeat n times the original string, returns a new string

'x'.repeat(3)      // "xxx" 
'hello'.repeat(2)  // "hellohello"