let trimString = function (string, length) {
      return string.length > length ? 
             string.substring(0, length) + '...' :
             string;
    };

用例,

let string = 'How to trim a string to N chars in Javascript';

trimString(string, 20);

//How to trim a string...

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。

只是另一个建议，删除任何尾随空白

limitStrLength = (text, max_length) => {
    if(text.length > max_length - 3){
        return text.substring(0, max_length).trimEnd() + "..."
    }
    else{
        return text
    }

首选String.prototype.slice而不是String.prototype.substring方法(在substring中，在某些情况下它给出的结果与您期望的结果不同)。

从左到右修剪字符串:

const str = "123456789";
result = str.slice(0,5);     // "12345", extracts first 5 characters
result = str.substring(0,5); // "12345"

startIndex > endIndex:

result = str.slice(5,0);     // "", empty string
result = str.substring(5,0); // "12345" , swaps start & end indexes => str.substring(0,5)

从右到左修剪字符串:(-ve start index)

result = str.slice(-3);                 // "789", extracts last 3 characters
result = str.substring(-3);             // "123456789" , -ve becomes 0 => str.substring(0)
result = str.substring(str.length - 3); // "789"

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)

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 ...