Javascript check multidimensional array if keys exists

Question

Hello I need to check 3 - dimensional json array, now I check it like this

if(events[dd][mm][rr] !== undefined){}

but if keys doesn't exists it throw's me an error. TypeError: events[dd] is undefined

I need some JS function to check if this condition is exists and throught error of TypeError. Thank you.

Answer 1

You'll have to check for each nested namespace. You could also write a recursive function if needed, if you have to check deeper into the map later on.

if (events[dd] && events[dd][mm] && events[dd][mm][rr] !== undefined) {}

Answer 2

Maybe use something like this:

function mdArrayExists(arr, var_args) {
    for (var i=1, k=arguments.length; i<k; ++i) {
        if (!arr || !arr.hasOwnProperty(arguments[i])
            return false;
        arr = arr[arguments[i]];
    }
    return true;
}

Usage:

if (mdArrayExists(events, dd, mm, rr) ...

Answer 3

我与这家公司没有任何隶属关系，但是每当我需要进行数组搜索时，我都会使用underscore.js库来执行此操作，因为该库具有许多用于快速查找数据的功能，并且性能明智的做法是节省开销如果我必须自己遍历数组。