Month Array in JavaScript Not Pretty

For a more natural approach, try this little snippet. It works with Date objects and just as a regular function:

'use strict';(function(d){    var mL = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];    var mS = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'June', 'July', 'Aug', 'Sept', 'Oct', 'Nov', 'Dec'];    d.prototype.getLongMonth = d.getLongMonth = function getLongMonth (inMonth) {        return gM.call(this, inMonth, mL);    }    d.prototype.getShortMonth = d.getShortMonth = function getShortMonth (inMonth) {        return gM.call(this, inMonth, mS);    }    function gM(inMonth, arr){        var m;        if(this instanceof d){            m = this.getMonth();        }        else if(typeof inMonth !== 'undefined') {            m = parseInt(inMonth,10) - 1; // Subtract 1 to start January at zero        }        return arr[m];    }})(Date);

You can directly copy and paste this, then use it like this:

var today = new Date();console.log(today.getLongMonth());console.log(Date.getLongMonth(9));          // Septemberconsole.log(today.getShortMonth());console.log(Date.getShortMonth('09'));      // Sept

This technique will provide flexibility as to how you index and how you access it. When using the Date object it will work correctly, but if using it as a standalone function it considers the months in human readable format from 1-12.

Fiddle with it!

this should do it ..

var months = {'01':'Jan', '02':'Feb'};alert( months['01'] );

Short Dynamic Solution:

Here's a dynamic solution that does not require hard-coding an array of months:

const month = f=>Array.from(Array(12),(e,i)=>new Date(25e8*++i).toLocaleString('en-US',{month:f}));

Test Cases:

// Using Number Index:month`long`[0];    // Januarymonth`long`[1];    // Februarymonth`long`[2];    // Marchmonth`short`[0];   // Janmonth`short`[1];   // Febmonth`short`[2];   // Marmonth`narrow`[0];  // Jmonth`narrow`[1];  // Fmonth`narrow`[2];  // Mmonth`numeric`[0]; // 1month`numeric`[1]; // 2month`numeric`[2]; // 3month`2-digit`[0]; // 01month`2-digit`[1]; // 02month`2-digit`[2]; // 03// Using String Index:let index_string = '01';month`long`[index_string-1];    // Januarymonth`short`[index_string-1];   // Janmonth`narrow`[index_string-1];  // Jmonth`numeric`[index_string-1]; // 1month`2-digit`[index_string-1]; // 01