:nth-of-type() in jQuery / Sizzle?

Question

It surprised me that Sizzle (the selector engine jQuery uses) comes with a built-in :nth-child() selector, but lacks an :nth-of-type() selector.

Answer 1

/**
 * Return true to include current element
 * Return false to exclude current element
 */
$.expr[':']['nth-of-type'] = function(elem, i, match) {
    if (match[3].indexOf("n") === -1) return i + 1 == match[3];
    var parts = match[3].split("+");
    return (i + 1 - (parts[1] || 0)) % parseInt(parts[0], 10) === 0;
};

Test case - (check in IE or rename the selector)

You can of course add even & odd too:

match[3] = match[3] == "even" ? "2n" : match[3] == "odd" ? "2n+1" : match[3];

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