根据JavaScript中的长度截断多行文本

Question

I have the following JavaScript code to truncate a string based on its length and add "..." at the end.

var elem = document.createElement('lengthDiv');
var text = "text to truncate";
elem.style.position = "absolute";
elem.style.whiteSpace = "nowrap";
elem.style.font = "helvetica";
elem.innerHTML = text;
document.documentElement.appendChild(elem);
var length = elem.clientWidth;
if (length > 298) {
    var i = 1;
    elem.innerHTML = '';
    while (elem.clientWidth < 298 && i < text.length) {
        elem.innerHTML = text.substr(0, i) + '...';
        i++;
    }
}
if (elem.clientWidth < 298 && i > 1) {
    while (elem.clientWidth < 298) {
        elem.innerHTML = elem.innerHTML + '.';
    }
}
var endresult = elem.innerHTML;

How do I make this code work for a single block of text where it will affect multiple lines of text? For example, I want to turn this:

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. 
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. 
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. 
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Into this (roughly):

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed... 
Ut enim ad minim veniam, quis nostrud exercitation ullamco l...
Duis aute irure dolor in reprehenderit in voluptate velit es...
Excepteur sint occaecat cupidatat non proident, sunt in culp...

I need it to be with only JavaScript , no JQuery or any other libraries.

Answer 1

I'd split your string and then truncate each item in that array. That would give you truncated sentences.

var res = text.split(".");

for (i = 0; i < res.length; i++) { 
        // truncate each sentence
}