Keep only first n characters in a string?

Solution 1:

const result = 'Hiya how are you'.substring(0,8);
console.log(result);
console.log(result.length);

You are looking for JavaScript's String method substring

e.g.

'Hiya how are you'.substring(0,8);

Which returns the string starting at the first character and finishing before the 9th character - i.e. 'Hiya how'.

substring documentation

Solution 2:

You could use String.slice:

var str = '12345678value';
var strshortened = str.slice(0,8);
alert(strshortened); //=> '12345678'

Using this, a String extension could be:

String.prototype.truncate = String.prototype.truncate ||
  function (n){
    return this.slice(0,n);
  };
var str = '12345678value';
alert(str.truncate(8)); //=> '12345678'

See also