Ellipsis in the middle of a text (Mac style)

Question

I need to implement ellipsis (\"...\") in the middle of a text within a resizable element. Here is what it might look like. So,

\"Lorem ipsum do         


        

Answer 1

The following Javascript function will do a middle truncation, like OS X:

function smartTrim(string, maxLength) {
    if (!string) return string;
    if (maxLength < 1) return string;
    if (string.length <= maxLength) return string;
    if (maxLength == 1) return string.substring(0,1) + '...';

    var midpoint = Math.ceil(string.length / 2);
    var toremove = string.length - maxLength;
    var lstrip = Math.ceil(toremove/2);
    var rstrip = toremove - lstrip;
    return string.substring(0, midpoint-lstrip) + '...' 
    + string.substring(midpoint+rstrip);
}       

It will replace characters in the middle with ellipsis. My unit tests show:

var s = '1234567890';
assertEquals(smartTrim(s, -1), '1234567890');
assertEquals(smartTrim(s, 0), '1234567890');
assertEquals(smartTrim(s, 1), '1...');
assertEquals(smartTrim(s, 2), '1...0');
assertEquals(smartTrim(s, 3), '1...90');
assertEquals(smartTrim(s, 4), '12...90');
assertEquals(smartTrim(s, 5), '12...890');
assertEquals(smartTrim(s, 6), '123...890');
assertEquals(smartTrim(s, 7), '123...7890');
assertEquals(smartTrim(s, 8), '1234...7890');
assertEquals(smartTrim(s, 9), '1234...67890');
assertEquals(smartTrim(s, 10), '1234567890');
assertEquals(smartTrim(s, 11), '1234567890');