D3.JS: Variable with getElementById default value

Question

I am creating a visualization in D3.js, in which I am importing the date through a dynamic string that requires a variable, which I named honeystring.

Variable

var honeyyear = document.getElementById("vardatayear");

Import

d3.json( `data/HoneyProduction-${honeyyear}.json`, function( honey_data ){...

Taking into account that Id element vardatayear does not exist before the display exists, as I guarantee that the variable has a value, such as 2013, if the element does not exist or is null?

That is, what you should do to assign a variable value, by default?

Answer 1

You can do it like this:

var honeyyear = document.getElementById("vardatayear") || 2013;

case document.getElementById("vardatayear") is null or does not exist to var honeyyear comes with 2013 value.

Or with a if you can too:

var honeyyear = document.getElementById("vardatayear")

if(!honeyyear){
    honeyyear  = 2013
}