this README contains how to run the code and also answer the additional tasks
yarn install
yarn subtask1
PRIVATE_KEY={privateKey} yarn subtask2
Q1: If the API returns the temperature in a decimal form (like 27.5 C), how to submit this decimal number to the smart contract while keeping its precision?
Since Fixed Point Numbers are not fully supported in solidity yet,
we can save the temperature by multitply 10**decimals in the contract, where
decimals can be a self define number depends on our use case.
We may divide the returned temperature by 10**decimals when we query from contracts
Q2: How to store a negative temperature while keeping the current smart contract interface unchanged?
Since the type for temperature in contract is uint32, we cannot store the exact value
of a negative integer to it. Instead, we could store the negative integer by adding
2**32-1 (the max number for uint32). For example, if we want to store -32, we could
store -32 + 2**32-1, which is 4,294,967,263. When retrieving the number, we could
deduct with 2**32-1 to restore the actual negative number.
Q3: During the "Step 3" in the task, it will take 3 JSON-RPC calls to read weather info for 3 cities from smart contract. Is it possbile to reduce that to only one request to get all the data back?
implemented in src/subtask2.ts, check out this file!