Library: Helpers and Math

Key takeaway: UniswapV2Library is the stateless math layer the Router depends on. It enforces canonical token ordering (token0 < token1) so every token pair maps to exactly one CREATE2-deployed Pair address, computes that address off-chain via the same keccak256 formula the Factory uses, and provides getAmountOut and getAmountIn with the 0.30% fee baked in (multiply by 997, divide by 1000) plus quote() for proportional reserve math. Every Router function calls into this library; getting any helper wrong cascades through the entire periphery.

What You Are Building

UniswapV2Library is a stateless library that provides the mathematical foundation the Router depends on. Every swap amount calculation, every pair address lookup, every reserve fetch goes through this library. It is pure math and address computation. No state, no storage, no external calls except one reserve fetch. Eight functions, each building on the previous ones.