Path in swap functions

[cryptofomo1]

Hi, hope you're well. It's quite hard to find relevant information when we are developing our own code so i try here hoping it may help other people.

I'm looking about getting the best price (meaning having the best 'path') before calling my swap function (ex swapExactTokensForXXX). So here the third parameter is the raw path provided but if you're using pancakeswap for ex, you'll see that before swapping it will be able to find for you the best route / path in order to provide you the best price. For ex instead of stupidly working with the pool token1/token2, it will propose a best price with the route token1/tokenX/token2, using different liquidity pools.

So my question is; do you have any clue about how to find the best route when dealing with these contracts ?

Thanks a lot,
Cheers.

[edit] Interesting links:
https://github.com/uniswap-integration/simple-uniswap-sdk#uniswap-pair-factory

[cryptofomo1]

Also i found that may be we just have to use the Route to automatically get the best path like this:

        const pair = await Fetcher.fetchPairData(INPUT_TOKEN, OUTPUT_TOKEN, provider);
        const route = await new Route([pair], INPUT_TOKEN);

When you are doing console.log(JSON.stringify(route)), you can see something like:

"path": [
    {
      "decimals": 18,
      "chainId": 56,
      "address": "0xblablabla"
    },
    {
      "decimals": 18,
      "chainId": 56,
      "address": "0xblablabla"
    }
  ]

So may be getting the path from here.

[religion-counter]

Hi @cryptofomo1 ,
Thank you for your interest and for the information provided.
I saw this in the SDK which seems to find the best pair and the best outputAmountMax:
https://github.com/Uniswap/v2-sdk/blob/20b63757676074c3d6b8f3a2c854b28c6045e357/src/entities/trade.ts#L214
https://docs.uniswap.org/sdk/2.0.0/reference/trade
bestTradeExactIn
I see they use this method to calculate output amount:
https://github.com/Uniswap/v2-sdk/blob/20b63757676074c3d6b8f3a2c854b28c6045e357/src/entities/pair.ts#L109
Which just calculates the left tokens in the liquidity pools to get the price.

[cryptofomo1]

Nice ! Thanks a lot mate i will dive into this asap, it looks promising.