我认为你应该使用这个代码:-)

    // sample string
            const param= "Hi you know anybody like pizaa";

         // You can change limit parameter(up to you)
         const checkTitle = (str, limit = 17) => {
      var newTitle = [];
      if (param.length >= limit) {
        param.split(" ").reduce((acc, cur) => {
          if (acc + cur.length <= limit) {
            newTitle.push(cur);
          }
          return acc + cur.length;
        }, 0);
        return `${newTitle.join(" ")} ...`;
      }
      return param;
    };
    console.log(checkTitle(str));

// result : Hi you know anybody ...

我认为你应该使用这个代码:-)

    // sample string
            const param= "Hi you know anybody like pizaa";

         // You can change limit parameter(up to you)
         const checkTitle = (str, limit = 17) => {
      var newTitle = [];
      if (param.length >= limit) {
        param.split(" ").reduce((acc, cur) => {
          if (acc + cur.length <= limit) {
            newTitle.push(cur);
          }
          return acc + cur.length;
        }, 0);
        return `${newTitle.join(" ")} ...`;
      }
      return param;
    };
    console.log(checkTitle(str));

// result : Hi you know anybody ...

将Will的评论复制到一个答案中，因为我发现它很有用:

var string = "this is a string";
var length = 20;
var trimmedString = string.length > length ? 
                    string.substring(0, length - 3) + "..." : 
                    string;

谢谢。

和一个jsfiddle为任何人谁关心https://jsfiddle.net/t354gw7e/:)

为了代码整洁，我建议使用扩展。 请注意，扩展内部对象原型可能会扰乱依赖于它们的库。

String.prototype.trimEllip = function (length) {
  return this.length > length ? this.substring(0, length) + "..." : this;
}

像这样使用它:

var stringObject= 'this is a verrrryyyyyyyyyyyyyyyyyyyyyyyyyyyyylllooooooooooooonggggggggggggsssssssssssssttttttttttrrrrrrrrriiiiiiiiiiinnnnnnnnnnnnggggggggg';
stringObject.trimEllip(25)

这是我的解决方案，其中也包括修剪空白。

const trimToN = (text, maxLength, dotCount) => {
  let modText = text.trim();

  if (modText.length > maxLength) {
    modText = text.substring(0, maxLength - dotCount);
    modText = modText.padEnd(maxLength, ".");

    return modText;
  }

  return text;
};

trimToN('Javascript'， 6,2)将返回“Java..”

有几种方法可以做到这一点

let description = "your test description your test description your test description";
let finalDesc = shortMe(description, length);

function finalDesc(str, length){

// return str.slice(0,length);

// return str.substr(0, length);

// return str.substring(0, length);

}

您还可以修改此函数以进入字符串之间。