Split string at space after certain number of characters in Javascript

Question

I am attempting to create a tool that takes an input text and splits it into chunks of text at a certain # of characters. However, I need to make sure it does not split the

Answer 1

A short and simple way to split a string into chunks up to a certain length using a regexp:

const chunks = str.match(/.{1,154}(\s|$)/g);

some examples:

const str = 'the quick brown fox jumps over the lazy dog';

console.log(str.match(/.{1,10}(\s|$)/g))
console.log(str.match(/.{1,15}(\s|$)/g))

This works because quantifiers (in this case {1,154}) are by default greedy and will attempt to match as many characters as they can. putting the (\s|$) behind the .{1,154} forces the match to terminate on a whitespace character or the end of the string. So .{1,154}(\s|$) will match up to 154 characters followed by a whitespace character. The /g modifier then makes it continue to match through the entire string.

To put this in the context of your function:

function splitText() {
    "use strict";
    var str = document.getElementById("user_input").value;
    var chunks = str.match(/.{1,154}(\s|$)/g);

    chunks.forEach(function (i,x) {
        $("#display").append("" + chunks[x] + "
");
    });
}

Note (as has been pointed out in the comments) that this code will fail if one of the words in the string is longer than the length of the chunks.