将文本从右到左分成多行，不能用连字符，其中行的最大长度为20个字符

1. you have a string "This is a test that has to be done using Javascript".Split into multiple lines of text without hyphenating words from right to left where the maximum length of the line is 20 characters(you can break only between words and the next line can't start with a space)

您有一个字符串“This is a test that has to be done using Javascript“。将文本从右到左分成多行，不能用连字符，其中行的最大长度为20个字符（只能在单词之间断开，下一行不能以空格开头）

"using Javascript

that has to be done

This is a test"

代码如下

function splitWordsReverse(s) {
    // 切割并翻转单词
    const words = s.split(' ').reverse();
    const arr = [];
    // 设置最大字符数
    const lengthMax = 20;
    // 遍历所有单词
    words.forEach(item => {
        if (arr[arr.length - 1] && arr[arr.length - 1].length + item.length + 1 <= lengthMax) {
            arr[arr.length - 1] = item + ' ' + arr[arr.length - 1];
        } else {
            arr.push(item)
        }
    });
    return arr.join('\n');
}

const res = splitWordsReverse('This is a test that has to be done using Javascript');
console.log(res);