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Chronological Updates

This file will contain all updates to sections.

Lesson 5

Windows, WSL, & Ganache​

  • Per this question, if you're using WSL, for the ganache UI you'll have to use a different endpoint.

You have 4 options to fix this:

  1. Use the WSL endpoint on the ganache UI (this sometimes doesn't work)
  2. Use ganache from the command line
  3. Use ganache-cli from the command line (not recommended)
  4. Just use hardhat from the command line (you'll have to use hardhat at some point anyways!)

Using the WSL Endpoint​

On the Ganache UI, you can select a different hostname and connect to whatever IP you see. In the example below, you'd connect to 172.24.224.1

You can also try to edit it by:

  1. Inside Ganache in the top-right corner tap on the gear icon (settings).
  2. Then in the server tab, change the HOSTNAME and select 0.0.0.0 - All Interfaces.

Using ganache​

yarn global add ganache
ganache

Keep this running in it's own terminal, and use the endpoint it gives you. To kill it, press CTRL + C.

See the discussion here

Using ganache-cli from the command line.​

Or, optionally, you can install ganache-cli as this user did.

yarn global add ganache-cli
ganache-cli

Keep this running in it's own terminal, and use the endpoint it gives you. To kill it, press CTRL + C.

Using hardhat​

See the discussion here

yarn add --dev hardhat
yarn hardhat

Then select the Create an empty hardhat.config.js

Then run:

yarn hardhat node

Keep this running in it's own terminal, and use the endpoint it gives you. To kill it, press CTRL + C.

Lesson 6

New Hardhat Setup​

As of 2.10.0 version of hardhat, when you first run yarn hardhat you'll get something like this instead:

888    888                      888 888               888
888    888                      888 888               888
888    888                      888 888               888
8888888888  8888b.  888d888 .d88888 88888b.   8888b.  888888
888    888     "88b 888P"  d88" 888 888 "88b     "88b 888
888    888 .d888888 888    888  888 888  888 .d888888 888
888    888 888  888 888    Y88b 888 888  888 888  888 Y88b.
888    888 "Y888888 888     "Y88888 888  888 "Y888888  "Y888

👷 Welcome to Hardhat v2.10.0 👷‍

? What do you want to do? … 
❯ Create a JavaScript project
  Create a TypeScript project
  Create an empty hardhat.config.js
  Quit

It's roughly similar to the options in our video, but you can just pick the JavaScript project whenever we don't pick the empty hardhat.config.js.

You can read more about the changes here.

Lesson 7

New Hardhat Setup​

As the previous section has highlighted, changes in the hardhat version changed the hardhat startup menu. You can choose to go with the new menu but if you feel lost and still want to access the old one used in the video, you can do so by installing hardhat v2.9.3

Run yarn add --dev hardhat@2.9.3

Lesson 9

Keepers new UI​

Per this conversation, when you get to the new Keepers UI, select "Custom Logic"

More information: https://github.com/smartcontractkit/full-blockchain-solidity-course-js/discussions/606#discussioncomment-3037792

Keepers Not Kicking Off Troubleshooting​

If your keepers are not kicking off, run through this checklist to find out why.

  1. Double check the subscription ID in your contract
  2. Double check the subscription is funded with enough LINK
  3. Is checkUpkeep returning true?
  4. Can you call performUpkeep yourself? (If you can't the keeper can't!)

Lesson 14

Math on NFT Chance Array​

The getBreedFromModdedRng() function in RandomIpfsNft.sol gets the math wrong.

line 104,

if (moddedRng >= cumulativeSum && moddedRng < cumulativeSum + chanceArray[i]) {
    return Breed(i);
}
cumulativeSum = cumulativeSum + chanceArray[i];

needs to be changed to

if (moddedRng >= cumulativeSum && moddedRng < chanceArray[i]) {
    return Breed(i);
}
cumulativeSum = chanceArray[i];

The chanceArray[] array already has a cumulative probability distribution, no need to keep adding cumulativeSum to it.

According to the current algorithm:

moddedRng produced is between 0 and 99
chanceArray=[10,30,100]
PUG is produced if moddedRng is between [0,10)  = span of 10
SHIBA is produce if moddedRng is between [10,40) = span of 30
BERNARD is produced if moddedRng is between [40,140] = span of 60 (since moddedRng<100)

So the actual probabilities according to the current algo is [10%,30%,60%] and not [10%,20%,70%] as would be expected from a proper cumulative probability distribution function.

Lesson 15

Metamask Troubleshooting while using Gitpod​

  • Remember if you are using gitpod then you cannot connect your local hardhat node with metamask. To resolve this you can use vs code or testnets instead of local node.

Large Update, please read

Moralis has recently updated to a self-hosted server over their own server. For this, you can do one of the following:

  • Learn how to run one yourself
  • Follow along to learn the concepts of this more interactive app, without actually coding along
  • Skip to the section where we interact with the graph

TL;DR: TheGraph code should work exactly the same as the video, however the Moralis code will not.