Retrieving an array from a JSON data structure

I encountered a JSON object like this:

var Events = {
    "Jan" : [],
    "Feb" : [],
    "Mar" : {
        "23" : [
            {"eventName" : "Start", "eventYear" : 2015, "eventDescription" : "First event description"},
            {"eventName" : "Start 2", "eventYear" : 2016, "eventDescription" : "Second event description"},
            {"eventName" : "Start 3", "eventYear" : 2017, "eventDescription" : "Third event description"}
        ],
        "24" : [
            {"eventName" : "Start", "eventYear" : 2015, "eventDescription" : "First event description for 24"},
            {"eventName" : "Start 2", "eventYear" : 2016, "eventDescription" : "Second event description for 24"}
        ]
    },
    "Apr" : [],
    "May" : [],
    "Jun" : [],
    "Jul" : [],
    "Aug" : [],
    "Sep" : [],
    "Oct" : [],
    "Nov" : [],
    "Dec" : []
}

I'm attempting to extract the events array for the current month:

window.addEventListener('DOMContentLoaded', init);
var date, month_names_short, thisMonthEvents;
function init(){
    date = new Date();
    month_names_short = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
    thisMonthEvents = Events.month_names_short[date.getMonth()];
};

However, I'm encountering an error message 

TypeError: Cannot read property '2' of undefined
on this line of code:

thisMonthEvents = Events.month_names_short[date.getMonth()];

Could someone please point out what mistake I am making and provide a solution? Thank you.

javascriptjson

Answer №1

To begin, locate the month name within the month_names_short array based on its index. Then, using bracket notation and the retrieved name, you can access the corresponding event:

function initialize() {
    currentDate = new Date();
    month_names_short = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
    thisMonthEvents = Events[month_names_short[currentDate.getMonth()]];
};

Answer №2

If you are considering utilizing the array containing abbreviated month names, here is one way to achieve that:

function initialize(){
    currentDate = new Date();
    monthNamesShort = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
    for (var idx in monthNamesShort) {
         var currentMonth = monthNamesShort[idx];
         thisMonthsEvents = Events[currentMonth];
    }
};

Answer №3

Replace "." with "[]" donation.

window.addEventListener('DOMContentLoaded', initialize);
var currentDate, shortMonthNames, currentMonthEvents;
function initialize(){
    currentDate = new Date();
    shortMonthNames = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
    currentMonthEvents = Events[shortMonthNames[currentDate.getMonth()]];
};

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