Unused and duplicate program constructs in o1js

[kantp]

The following program constructs are unused or have repeated functionality which could be abstracted into a common function.

• src/lib/mina/token/token-methods.ts:
  • tokenMethods(): mint(), burn(), and send() all recompute the derived token id before calling getApprovedUpdate(). Consider computing the derived token ID within the getApprovedUpdate() function.
    To avoid recomputing the derived token ID in send(), the developers could have getApprovedUpdate() take the token ID as an optional parameter, and return the computed value.

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• src/lib/mina/token/token-contract.ts:
  • TokenContract.approveAccountUpdate(): This function duplicates most of the body of approveAccountUpdates().

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• o1js/src/lib/provable/merkle-list.ts:
  • from(), fromReverse(): Note that from(array) is simply fromReverse([...array].reverse()), but both functions instead implement the same logic.
  • MerkleListIterator, MerkleListIterator.Unsafe: Both objects implement previous() and next() methods which share the majority of their logic.