更健壮的:

function trim(word)
{
    word = word.replace(/[^\x21-\x7E]+/g, ' '); // change non-printing chars to spaces
    return word.replace(/^\s+|\s+$/g, '');      // remove leading/trailing spaces
}

var string = "The dog      has a long   tail, and it     is RED!";
var replaced = string.replace(/ +/g, " ");

或者如果你也想替换制表符:

var replaced = string.replace(/\s+/g, " ");

假设你还想覆盖制表符、换行符等，只需将\s\s+替换为' ':

string = string.replace(/\s\s+/g, ' ');

如果你真的只想覆盖空格(而不是制表符，换行符等)，可以这样做:

string = string.replace(/  +/g, ' ');

更健壮的:

function trim(word)
{
    word = word.replace(/[^\x21-\x7E]+/g, ' '); // change non-printing chars to spaces
    return word.replace(/^\s+|\s+$/g, '');      // remove leading/trailing spaces
}

var text = `xxx  df dfvdfv  df    
                     dfv`.split(/[\s,\t,\r,\n]+/).filter(x=>x).join(' ');

结果:

"xxx df dfvdfv df dfv"

我知道我们必须使用正则表达式，但在一次采访中，我被要求不要使用正则表达式。

@slightlytyler帮助我提出了下面的方法。

const testStr = "I LOVE STACKOVERFLOW LOL"; const removeSpaces = str => { Const chars = str.split("); const nextChars = char .reduce( (acc, c) => { If (c === ' ') { const lastChar = acc[acc.]长度- 1]; if (lastChar === ' ') { 返回acc; } } 返回[…acc, c]; }， [], ）; const nextStr = nextchar .join("); 返回nextStr }; console.log (removeSpaces (testStr));