js正则替换replace

str.replace(regexp|substr, newSubstr|function)

let str = "Hello, world!";
let newStr = str.replace("world", "everyone");
console.log(newStr); // 输出: "Hello, everyone!"

let str = "apple orange apple banana";
let newStr = str.replace(/apple/g, "pear");
console.log(newStr); // 输出: "pear orange pear banana"

let str = "Hello World! hello world!";
let newStr = str.replace(/hello/gi, "Hi");
console.log(newStr); // 输出: "Hi World! Hi world!"

let str = "The price is $100 and $200";
let newStr = str.replace(/\$\d+/g, function(match) {
    return parseInt(match.slice(1)) * 2;
});
console.log(newStr); // 输出: "The price is 200 and 400"

let str = "apple apple apple";
let newStr = str.replace(/apple/g, "orange"); // 添加了"g"标志
console.log(newStr); // 输出: "orange orange orange"

let str = "The quick brown fox jumps over the lazy dog";
let newStr = str.replace(/\b\w{4}\b/g, function(match) {
    return match.toUpperCase();
});
console.log(newStr); // 输出: "The QUICK BROWN fox JUMPS over the LAZY dog"