Convert Numerals to Ordinal Equivalent Using JavaScript

Ordinal numbers are the word representations of the rank of a number with respect to its order.



Here we are going to convert those numeral (e.g. 1, 2, 3, etc.) values to it's ordinal equivalent.

Sample and Analysis

By mathematical rule:

• if a numeral ends with 1, the number is followed by "st"
• if a numeral ends with 2, the number is followed by "nd"
• if a numeral ends with 3, the number is followed by "rd"
• else, the number is followed by "th"

Thus it should look like this:

1 = 1st
2 = 2nd
11 = 11th
20 = 20th
31 = 31st
101 = 101st

The JavaScript Code

var ordinalize = function(number){
    number += '';

    if(isNaN(number)) return number;

    if(number.length === 1){
        if (number === '1') return number + "st";
        if (number === '2') return number + "nd";
        if (number === '3') return number + "rd";
        if (number != '1'&& number != '2' && number != '3') return number + "th"
    } else {
        secLast = number[number.length - 2];
        lastLast = number[number.length - 1];
        if (secLast === '1') return number + 'th';
        else {
            if (lastLast === '1') return number + "st";
            if (lastLast === '2') return number + "nd";
            if (lastLast === '3') return number + "rd";
            if (lastLast != '1' && lastLast != '2' && lastLast != '3') return number + "th"
        }
    }
};

Usage

To use simply call ordinalize(NUMBER) and it will return the ordinalize version. If in case a string was passed, the same value would be return.