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https://github.com/pooltogether/draw-calculators-js
Stateless Typescript library for the v4 Draw Calculator
https://github.com/pooltogether/draw-calculators-js
Last synced: about 2 months ago
JSON representation
Stateless Typescript library for the v4 Draw Calculator
- Host: GitHub
- URL: https://github.com/pooltogether/draw-calculators-js
- Owner: pooltogether
- Created: 2021-08-09T18:59:01.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2021-12-02T01:21:24.000Z (about 3 years ago)
- Last Synced: 2024-04-23T21:42:35.459Z (9 months ago)
- Language: TypeScript
- Homepage:
- Size: 26.1 MB
- Stars: 5
- Watchers: 3
- Forks: 4
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# PoolTogether Draw Calculator JS
[](https://github.com/pooltogether/draw-calculators-js/actions/workflows/main.yml)
[](https://badge.fury.io/js/@pooltogether%2Fdraw-calculator-js)
[](https://definitelytyped.org)
This library includes a stateless Typescript model of the Solidity DrawCalculator. It is intended to be uses as a tool to easily check if a User has won a prize for a particular draw. This could also be calculated on-chain through the `DrawCalculator::calculate()` view function but this library is much faster.
# Setup
This project is available as an NPM package:
```bash
$ yarn add @pooltogether/draw-calculator-js
```
# How to use
To create a claim or calculate winnings for an address:
1. Run `yarn add @pooltogether/draw-calculator-js` in your project to install the package.
1. Import the desired functions and types: `import {drawCalculator, Draw, PrizeDistribution, DrawResults, filterResultsByValue, generatePicks, prepareClaims } from "@pooltogether/draw-calculator-js"`
Starting with a particular `drawId` and `userAddress`, fetch the Draw information from the DrawBuffer contract:
```js
const drawBuffer: Contract = new ethers.Contract(address, drawBufferAbi, signerOrProvider);
const drawId: number = await drawBuffer.getNewestDraw(); // can go back cardinality in time (8 draws)
const draw: Draw = await drawBuffer.functions.getDraw(drawId); // read-only rpc call
```
Next fetch the PrizeDistribution for the `drawId` from the PrizeDistributionBuffer contract:
```javascript
// get PrizeDistribution from the DrawCalculatorHistory contract for a particular drawId
const PrizeDistributionBufferContract: Contract = new ethers.Contract(
address,
prizeDistributionAbi,
signerOrProvider,
);
const prizeDistribution = await PrizeDistributionBufferContract.functions.getPrizeDistribution(
drawId,
); // read-only rpc call
```
Next, get the users balance using the convenient `getNormalizedBalancesForDrawIds(address _user, uint32[] calldata _drawIds)` view method
on the DrawCalculator contract which returns an array of balances for drawIds:
W
```js
const drawCalculator: Contract = new ethers.Contract(address, drawCalculatorAbi, signerOrProvider);
const balances = await drawCalculator.functions.getNormalizedBalancesForDrawIds(userAddress, [
drawId,
]); // read-only rpc call
```
Run this `draw-calculator-js` library locally to see the user has any prizes to claim:
```js
const exampleUser: User = {
address: userAddress // user address we want to calculate for
normalizedBalances: balances
}
let results: DrawResults = batchCalculateDrawResults([prizeDistribution], [draw], exampleUser)
```
The `results.totalValue` field should indicate the total amount of prize available for `userAddress` for the `drawId`.
These results may then need to be filtered by value, since the user can only claim `prizeDistribution.maxPicksPerUser` number of prizes per draw.
```js
results = filterResultsByValue(results, prizeDistribution.maxPicksPerUser);
```
Finally, to claim a prize, forward these `DrawResults` to `prepareClaims(user: User, drawResult: DrawResults[])` to generate the data for the on-chain PrizeDistributor `claim()` call:
```js
const claim: Claim = prepareClaims(user, [results]);
```
The on-chain call to `PrizeDistributor::claim(address _user, uint32[] calldata _drawIds, bytes calldata _data)` can then be populated and called with this data:
```js
const PrizeDistributorContract = new ethers.Contract(
address,
PrizeDistributorAbi,
signerOrProvider,
);
await PrizeDistributorContract.functions.claim(
claim.userAddress,
claim.drawIds,
claim.encodedWinningPickIndices,
); //write rpc call
```
Congratulations you have now claimed a prize!
# API Guide
todo.
# Types
A full breakdown of the types can be found [here](./src/types.ts)
# Testing
Unit tests can be run using:
```bash
$ yarn test
```
# Development
Fork/clone this repo. Create a pull request with the changes you would like to make. Unit tests must be passing.