没有内置方法?鉴于Javascript中的字符串是不可变的，您可能希望使用内置的方法，如split、join等。但这里有两种不使用这些方法的方法:

function ReverseString(str) {
    var len = str.length;
    var newString = [];

    while (len--) {
        newString.push(str[len]);
    }

    return newString.join('');
}

console.log(ReverseString('amgod')) //dogma

function RecursiveStringReverse(str, len) {
    if (len === undefined)
        len = str.length - 1;

    if (len > 0)
        return str[len] + RecursiveReverse(str, --len);

    return str[len];
}

console.log(RecursiveStringReverse('Hello, world!'))// !dlrow ,olleH

我想，这对你有用

function reverse(str){
    str = str.split("").reverse().join("").split(" ").reverse().join(" ");
    console.log(str)
}

这样的事情应该遵循最佳实践:

(function(){ 'use strict'; var str = "testing"; //using array methods var arr = new Array(); arr = str.split(""); arr.reverse(); console.log(arr); //using custom methods var reverseString = function(str){ if(str == null || str == undefined || str.length == 0 ){ return ""; } if(str.length == 1){ return str; } var rev = []; for(var i = 0; i < str.length; i++){ rev[i] = str[str.length - 1 - i]; } return rev; } console.log(reverseString(str)); })();

//recursive implementation
function reverse(wrd) {
  const str =wrd[0]
  if(!wrd.length) {
    return wrd
  }
  return reverse(wrd.slice(1)) + str
}

以下是可以用来实现字符串反转的四种最常用方法

给定一个字符串，返回一个新字符串 字符顺序

问题的多种解决方案

//reverse('apple') === 'leppa'
//reverse('hello') === 'olleh'
//reverse('Greetings!') === '!sgniteerG'

// 1. First method without using reverse function and negative for loop
function reverseFirst(str) {
    if(str !== '' || str !==undefined || str !== null) {
        const reversedStr = [];
        for(var i=str.length; i>-1; i--) {
        reversedStr.push(str[i]);
        }
    return reversedStr.join("").toString();
    }
}

// 2. Second method using the reverse function
function reverseSecond(str) {
    return str.split('').reverse().join('');
}

// 3. Third method using the positive for loop
function reverseThird(str){
    const reversedStr = [];
    for(i=0; i<str.length;i++) {
        reversedStr.push(str[str.length-1-i])
    }
    return reversedStr.join('').toString();
}

// 4. using the modified for loop ES6
function reverseForth(str) {
    const reversedStr = [];
    for(let character of str) {
        reversedStr = character + reversedStr;
    }
    return reversedStr;
}

// 5. Using Reduce function
function reverse(str) {
    return str.split('').reduce((reversed, character) => {
        return character + reversed;  
    }, '');
}

使用Array函数，

String.prototype.reverse = function(){
    return [].reduceRight.call(this, function(last, secLast){return last + secLast});
}