Fulfilling Orders *currently listed* on Opensea

[0xAskar]

``Hey yall, thanks for the help on my other post, currently getting fulfillOrder to work out. But, how would I be able to create an order fior an already listed item on Opensea (thus not needing the permission of the offerer during real-time) and thus, just have the buyer approve and confirm the transaction? This is where I'm confused on how to use fullFill order in that sense. The idea I got from a friend is to make the createOrder the opposite ETH for ERC721 so that the first signature is to get buyer's approval and thus on opensea it should already be approved. But, does seaport check for listings already on Opensea?

Another Update: My friend suggested possibly trying out Retrieve Orders from the api, to get the order and signature and then past that into fulfillOrder along with signature? That seems like a much better way, but not sure how to do it syntactically, but I'll try that out. If anyone knows if thats the best way to go about, an example would help!

Here's what I have so far for this currently listed item. However, the problem is, I'm able to sign the transaction for the fulfiller, but then get a weird error seen in the image

`const seller = "0x94DBCE8a42E2F578ad80266863bc9C7d2e04ea6A"
const offerer = "0xDF93B5ec8Eb9407F03fF14a2E2B3eE4196fcD8b0"
let order = null
const sell = async() => {
if (typeof seaport !== "undefined") {
const {executeAllActions} = await seaport.createOrder({
offer: [
{
amount: "100000000000000000",
token: "0x0000000000000000000000000000000000000000",
identifier: "0"
}
],
consideration: [
{
itemType: ItemType.ERC721,
amount: "1",
token: "0x569f26145f0c2fcc3da68395be3639009c53b6d8",
identifier: "546",
recipient: Web3.utils.toChecksumAddress(offerer) //offerer, which is the seller in this case to list it
}
]
})
const executedOrder = await executeAllActions()
order = executedOrder
}
}

    const buy = async() => {
        if (typeof seaport !== "undefined" && order) {
            const { executeAllActions: executeAllFullfillActions} = await seaport.fulfillOrder({
                order: order,
                accountAddress: seller
            })
            
            const transaction = await executeAllFullfillActions()
        }
    }`

[0xAskar]

I was able to figure it out with a friend! You can use the Retrieve Orders Opensea api call to get the order with the signature so then you're able to just need the buyer's signature.

       const buy = async() => {
            const provider = new ethers.providers.Web3Provider(window.ethereum);
            const seaport = new Seaport(provider);
            //get the asset from "Retrieve Assets from the api"
            // see the link https://docs.opensea.io/reference/getting-assets
            // then parse out the ["assets"]["seaport_sell_orders"]["protocol_data"]
            let full_order = output["assets"]["seaport_sell_orders"]["protocol_data"]
            if (typeof seaport !== "undefined" && full_order) {
                console.log("inside")
                const { executeAllActions: executeAllFullfillActions} = await seaport.fulfillOrder({
                    order: full_order,
                    accountAddress: buyer
                })
                
                const transaction = await executeAllFullfillActions()
                console.log(transaction)
            }
        }