How can I set a character limit of 100 without splitting words?

Question

I want to cut a string every 100 characters without cutting up words.

var TmpArray=[];
var str = 'this string will be cut up after every 100 characters but it will cut into words';
str=str.replace(/[^a-z A-Z0-9]+/g, '');
str = str.replace(/\s{2,}/g, ' ');
var sp=(str.match(new RegExp(" ", "g")) || []).length;
var max=100;
//Spaces will be converted into %20 (later) so each space must count as 3 characters.
var FoundSpaces=sp*3;
var tmp=max-FoundSpaces;
var cut=str.match(new RegExp('.{1,'+tmp+'}', 'g'));
for (i = 0; i < cut.length; i++){
    TmpArray.push(cut[i]);
}
console.log(TmpArray);

Output: ["this string will be cut up after every 100 characters b", "ut it will cut into words"]

So how can I prevent it from splitting words like it did?

Answer 1

Interesting question. I will propose one more implementation of how you can use just array methods, combination of split + reduce:

var str = 'This example of the string that we want to split by spaces only making sure that individual chunk is less or equal to specified number.';

// Split by spaces
str.split(/\s+/)

// Then join words so that each string section is less then 40
.reduce(function(prev, curr) {
    if (prev.length && (prev[prev.length - 1] + ' ' + curr).length <= 40) {
        prev[prev.length - 1] += ' ' + curr;
    }
    else {
        prev.push(curr);
    }
    return prev;
}, [])

// Print for testting
.forEach(function(str) {
    console.log(str + ' ' + str.length);
});

For this example I set maximum length of 40 characters.

Output:

This example of the string that we want 39
to split by spaces only making sure that 40
individual chunk is less or equal to 36
specified number. 17

One more demo: http://jsfiddle.net/9tgo6n1t/