I've adapted a PHP script lifted from another project to use in JavaScript, this script works great for shortening text to a set limit. I would like to use it to also split it to multiple parts if it is over the set limit.

The current code which shortens once is here: /

Here's what I have so far: / (I'm pretty sure I'm not doing it right)

I have gotten stuck in loops a few to many times, I'm not sure how to proceed with it.

function strTruncate($string, $your_desired_width) {

    arr = [];

    if (typeof($last_part)) {
        $last_part = 0;
    }

    $parts = $string.split(/([\s\n\r]+)/);
    $parts_count = $parts.length;

    $length = 0;
    $last_part = 0;
    for (; $last_part < $parts_count; ++$last_part) {
        $length += $parts[$last_part].length;
        if ($length > $your_desired_width) {
            break;
        }
    }

    $start_part = 0;

    return $parts.slice($start_part, $last_part).join('');

}

Shorten Once Result:

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer malesuada, est ut interdum ullamcorper, metus lorem interdum ipsum, vitae

New Expected Result:

array[0] = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer malesuada, est ut interdum ullamcorper, metus lorem interdum ipsum, vitae",
array[1] = "vulputate ante quam ut augue. Praesent sit amet varius lorem. Aliquam odio nunc, mattis in mollis vitae, laoreet non velit. Curabitur"
array[2] = "adipiscing, nisl tincidunt consequat ornare, ligula mauris sed."

I've adapted a PHP script lifted from another project to use in JavaScript, this script works great for shortening text to a set limit. I would like to use it to also split it to multiple parts if it is over the set limit.

The current code which shortens once is here: http://jsfiddle/WilliamIsted/P5jxK/

Here's what I have so far: http://jsfiddle/WilliamIsted/UkhXL/ (I'm pretty sure I'm not doing it right)

I have gotten stuck in loops a few to many times, I'm not sure how to proceed with it.

function strTruncate($string, $your_desired_width) {

    arr = [];

    if (typeof($last_part)) {
        $last_part = 0;
    }

    $parts = $string.split(/([\s\n\r]+)/);
    $parts_count = $parts.length;

    $length = 0;
    $last_part = 0;
    for (; $last_part < $parts_count; ++$last_part) {
        $length += $parts[$last_part].length;
        if ($length > $your_desired_width) {
            break;
        }
    }

    $start_part = 0;

    return $parts.slice($start_part, $last_part).join('');

}

Shorten Once Result:

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer malesuada, est ut interdum ullamcorper, metus lorem interdum ipsum, vitae

New Expected Result:

array[0] = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer malesuada, est ut interdum ullamcorper, metus lorem interdum ipsum, vitae",
array[1] = "vulputate ante quam ut augue. Praesent sit amet varius lorem. Aliquam odio nunc, mattis in mollis vitae, laoreet non velit. Curabitur"
array[2] = "adipiscing, nisl tincidunt consequat ornare, ligula mauris sed."

• javascript
• split
• slice

• 1 Please post your code here, not on some unrelated page. An additional demo is nice, but the relevant code belongs to the question. – Bergi Commented Nov 21, 2012 at 19:36
• 2 Please, replace all uses of .count() with .length. It hurts :-) – Bergi Commented Nov 21, 2012 at 19:37
• @Bergi Good call, I tried .length() before, obviously that didn't work. – William Isted Commented Nov 21, 2012 at 19:40

4 Answers 4

Your code is a bit messy, it can be rewritten to something like this

function strTruncate(string, width) { // your original function
    string = string.replace(/[\s\r\n]+/, ' ');
    if(string.length >= width) {
        return string[width-1] === ' ' ? string.substr(0, width - 1) : string.substr(0, string.substr(0, width).lastIndexOf(' '));
    }
    return string;
}
function strTruncateWhole(string, width) { // function that stores result(s) in array
    arr = [];
    string = string.replace(/[\s\r\n]+/, ' ');
    var b = 0;
    while(b < string.length) {
        arr.push(strTruncate(string.substring(b), width));
        b += arr[arr.length-1].length;
    }
    return arr;
}

I believe what you're looking for is a script like this:

function strSplitOnLength(data, your_desired_width) {
    if(data.length <= 0)
        return [];  // return an empty array

    var splitData = data.split(/([\s\n\r]+)/);
    var arr = [];
    var cnt = 0;
    for (var i = 0; i < splitData.length; ++i) {
        if (!arr[cnt]) arr[cnt] = '';  //Instantiate array entry to empty string if null or undefined

        if (your_desired_width < (splitData[i].length + arr[cnt].length))
            cnt++;

        arr[cnt] += splitData[i];
    }

    return arr;
}

strSplitOnLength('Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer malesuada, est ut interdum ullamcorper, metus lorem interdum ipsum, vitae vulputate ante quam ut augue. Praesent sit amet varius lorem. Aliquam odio nunc, mattis in mollis vitae, laoreet non velit. Curabitur adipiscing, nisl tincidunt consequat ornare, ligula mauris sed.', 140);​

Just go on with the loop. Instead of breaking and returning the parts from start to last only, splice them out of the array, reset your width count and push them on a result array.

Also notice that other than in PHP you need to declare all local variables with var; and also there is no boolean typeof function but a keyword that returns the string "undefined" (not sure what you wanted to do there anyway).

function strTruncate(str, maxWidth) { // not sure whether that's the best name
    var resultArr = [];
    var parts = str.split(/([\s\n\r]+)/);
    var count = parts.length;
    var width = 0;
    var start = 0;
    for (var i=0; i<count; ++i) {
        width += parts[i].length;
        if (width > maxWidth) {
            resultArr.push( parts.slice(start, i).join('') );
            start = i;
            width = 0;
        }
    }
    return resultArr;
}

var str='Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer malesuada, est ut interdum ullamcorper, metus lorem interdum ipsum, vitae.';
var parts=4
console.log(divideText(str,parts))

function divideText(text, parts) {
   var split=/[\s\n\r]/g
  return text.split(split).reduce((arr, el, i) => {
    const index = Math.floor(i * parts / text.split(split).length);
    arr[index] = arr[index] ? arr[index] + " " + el : el;
    return arr;
  }, []);
}