nikitha nikitha - 1 year ago 97
Javascript Question

how do you sort an array with empty strings, NaN, numbers and infinity

I'm trying to sort an array that includes empty strings, numbers, "infinity", "-infinity", and "NaN". I am receiving all the values in form of strings, so sort is not working as expected when it comes to empty strings, inf and nan. Is there a way to customize my sort function both in ascending and descending order?

Answer Source

Edit: according to your comment, "" < "-inf" < "Nan" < "inf" < ... < -1 < 0 < 1 < ... . You can change this by modifying the order array.

Note this code will not work properly if the array contains elements that are not present in the order array. You can either set guards for that, or add other special elements (like 0) to the order array.

Also note NaN and Infinity (not a string literals) are also a number in javascript. Using this code, they will be ordered next to numbers.

var basicCompare = function (a, b) {
    if (a > b) return 1;
    if (a < b) return -1;
    return 0;

var compare = function (a, b) {
    // 0 represents numbers.
    var order = ["", "-inf", "Nan", "inf", 0],
        orderOfNumber = order.indexOf(0),   
        orderOfA = typeof(a) === "number" ? orderOfNumber : order.indexOf(a),
        orderOfB = typeof(b) === "number" ? orderOfNumber : order.indexOf(b);

    if (orderOfA === orderOfNumber & orderOfB === orderOfNumber) {
        // They are both numbers, use regular comparison.
        return basicCompare(a, b);

    // They are not both numbers, so use the axiomatic order.
    return basicCompare(orderOfA, orderOfB)

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