A javascript function to word wrap given a long string and a max line length

wordWrap

var wordwrap = function(long_string, max_char){

  var sum_length_of_words = function(word_array){
    var out = 0;
    if (word_array.length!=0){
      for (var i=0; i<word_array.length; i++){
        var word = word_array[i];
        out = out + word.length;
      }
    };
    return out;
  }

  var split_out = [[]];
  var split_string = long_string.split(' ');
  for (var i=0; i<split_string.length; i++){
    var word = split_string[i];
    
    if ((sum_length_of_words(split_out[split_out.length-1]) + word.length) > max_char){
      split_out = split_out.concat([[]]);
    }
    
    split_out[split_out.length-1] = split_out[split_out.length-1].concat(word);
  }
  
  for (var i=0; i<split_out.length; i++){
    split_out[i] = split_out[i].join(" ");
  }
  
  return split_out.join('\n');
};

var test_string = "this is a long string that should be word wrapped, hopefully";

console.log("the following should be wrapped");
console.log(wordwrap(test_string, 20));

It would be nice to cut the words also when there length is also greater than the max_char:

var wordwrap = function(long_string, max_char){

    var sum_length_of_words = function(word_array){
        var out = 0;
        if (word_array.length!=0){
            for (var i=0; i<word_array.length; i++){
                var word = word_array[i];
                out = out + word.length;
            }
        };
        return out;
    };


    var chunkString = function (str, length){
        return str.match(new RegExp('.{1,' + length + '}', 'g'));
    };

    var splitLongWord = function (word, maxChar){
        var out = [];
        if( maxChar >= 1){
            var wordArray = chunkString(word, maxChar-1);// just one under maxChar in order to add the innerword separator '-'
            if(wordArray.length >= 1){
                // Add every piece of word but the last, concatenated with '-' at the end
                for(var i=0; i<(wordArray.length-1); i++){
                    var piece = wordArray[i] + "-";
                    out.push(piece);
                }
                // finally, add the last piece
                out.push(wordArray[wordArray.length-1]);
            }
        }
        // If nothing done, just use the same word
        if(out.length == 0) {
            out.push(word);
        }
        return out;
    }

    var split_out = [[]];
    var split_string = long_string.split(' ');
    for(var i=0; i<split_string.length; i++){
        var word = split_string[i];

        // If the word itself exceed the max length, split it,
        if(word.length > max_char){
            var wordPieces = splitLongWord(word, max_char);
            for(var i=0;i<wordPieces.length;i++){
                var wordPiece = wordPieces[i];
                split_out = split_out.concat([[]]);
                split_out[split_out.length-1] = split_out[split_out.length-1].concat(wordPiece);
            }

        } else {
            // otherwise add it if possible
            if ((sum_length_of_words(split_out[split_out.length-1]) + word.length) > max_char){
              split_out = split_out.concat([[]]);
            }

            split_out[split_out.length-1] = split_out[split_out.length-1].concat(word);
        }
    }

    for (var i=0; i<split_out.length; i++){
        split_out[i] = split_out[i].join(" ");
    }

    return split_out.join('\n');
};

var test_string = "this is a long string that should be word wrapped, hopefully";
var test_string2 = "thereisanotherlongstringthatshouldbewordwrapped,hopefully";
var test_string3 = "thereisanotherlongstringthat should also be word wrapped, hopefully";

console.log("the following should be wrapped");
console.log(wordwrap(test_string, 20));
console.log(wordwrap(test_string2, 20));
console.log(wordwrap(test_string3, 20));

http://james.padolsey.com/snippets/wordwrap-for-javascript/

This is not working
for following input
console.log(wordwrap(test_string, 7));

var wordwrap = function(long_string, max_char){
if (long_string== null) { return " "; }
else {

var sum_length_of_words = function(word_array){
    var out = 0;
    if (word_array.length!=0){
        for (var i=0; i<word_array.length; i++){
            var word = word_array[i];
            out = out + word.length;
        }
    };
    return out;
};


var chunkString = function (str, length){
    return str.match(new RegExp('.{1,' + length + '}', 'g'));
};

var splitLongWord = function (word, maxChar){
    var out = [];
    if( maxChar >= 1){
        var wordArray = chunkString(word, maxChar-1);// just one under maxChar in order to add the innerword separator '-'
        if(wordArray.length >= 1){
            // Add every piece of word but the last, concatenated with '-' at the end
            for(var i=0; i<(wordArray.length-1); i++){
                var piece = wordArray[i] + "-";
                out.push(piece);
            }
            // finally, add the last piece
            out.push(wordArray[wordArray.length-1]);
        }
    }
    // If nothing done, just use the same word
    if(out.length == 0) {
        out.push(word);
    }
    return out;
}

var split_out = [[]];
var split_string = long_string.split(' ');
for(var i=0; i<split_string.length; i++){
    var word = split_string[i];

    // If the word itself exceed the max length, split it,
    if(word.length > max_char){
        var wordPieces = splitLongWord(word, max_char);
        for(var j=0;j<wordPieces.length;j++){
            var wordPiece = wordPieces[j];
            split_out = split_out.concat([[]]);
            split_out[split_out.length-1] = split_out[split_out.length-1].concat(wordPiece);
        }

    } else {
        // otherwise add it if possible
        if ((sum_length_of_words(split_out[split_out.length-1]) + word.length+1) > max_char){
          split_out = split_out.concat([[]]);
        }

        split_out[split_out.length-1] = split_out[split_out.length-1].concat(word);
    }
}

for (var i=0; i<split_out.length; i++){
    split_out[i] = split_out[i].join(" ");
}

return split_out.join('\n');

};

HTML

JS

 function createDiv(text) {
     var div = document.createElement("DIV");
     div.classList.add("line");
     div.innerHTML = text;
     document.getElementById('wordWrap').appendChild(div);
 }

 function wordWrap(str, charMax) {
        let arr = [];
        let space = /\s/;

        const words = str.split(space);
        // push first word into new array
        if (words[0].length) {
            arr.push(words[0]);
        }

        for (let i = 1; i < words.length; i++) {
            if (words[i].length + arr[arr.length - 1].length < charMax) {
                arr[arr.length - 1] = `${arr[arr.length - 1]} ${words[i
                ]}`;
            } else {
                arr.push(words[i]);
            }
        }

        //console.log('arr', arr);
        return arr;
    }
    var str = 'The quick, brown fox jumped over the lazy dog';
   let output =  wordWrap(str, 6);
   console.log(output);

   output.forEach(line => createDiv(line));