CODEWITHSUNDEEP
javascriptarraysnode.jsdiscord.js
Nathaniel Rose
Nathaniel Rose

Reputation: 39

Why does join(", ") not work with my array?

I'm trying to make a discord bot for something, and I can't figure out why this is happening. In retrospect, this isn't really a big issue, but it would be a good idea to know the reasoning

Essentially, I have an array that looks something like this: 

// Boosters.js
exports.test = ["Card", "Card2", "Card3", "Card4", "Card5", 
                "Card6", "Card7", "Card8", "Card9", "Card10"];

Then, in another file, I have a function:

// Functions.js
var pack = [];

let getCards = function getCards()
{
    var obtainedCards = [];

    for(i = 0; i < 7; i++)
    {
        var cards = Boosters.test[Math.floor(Math.random() * Boosters.test.length)];
        obtainedCards.push(cards);
    }

   // Adds the cards from the obtained cards variable to the pack
   pack.push(obtainedCards);

}

Then in a third file, I have a command that will call the function like so:

// 
case "pack":
    Functions.getCards();
    message.channel.send("Cards obtained: " + Functions.pack.join(", "));

No issues here, it works. The problem is, in Discord it'll look like:

Cards obtained: Card1,Card5,Card2,Card6,Card2,Card1,Card7

Basically, it ignores the join() function. The weird thing is if I print the original test[], the bot actually spaces everything out using join(", "). So I don't know what the difference is.

Upvotes: 1

Views: 198

Answers (1)

sdgfsdh
sdgfsdh

Reputation: 37045

This line is likely the culprit:

obtainedCards.push(cards);

To see why, consider this code:

let xs = [ 'x', 'y', 'z' ];

xs.push([ 'a', 'b', 'c' ]);

// xs is now: 
// [ 'x', 'y', 'z', [ 'a', 'b', 'c' ] ] 
//
// ... but you might have expected this: 
// [ 'x', 'y', 'z', 'a', 'b', 'c' ]

If we join(', ') this, the [ 'a', 'b', 'c' ] element is converted to a string:

xs.join(', ') // "x, y, z, a,b,c"

Note the lack of spaces!

This behaviour occurs whenever an array is automatically converted to a string:

'xyz' + [ 'a', 'b', 'c' ] // "xyza,b,c"

To fix it, try this change:

obtainedCards = obtainedCards.concat(cards);

Upvotes: 1

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