How I automated the Anchor IDL v0 to v1 migration with a codemod

A developer created a codemod to automate the migration of Anchor IDL v0 to v1, which is necessary due to Anchor's redesigned IDL specification. This migration is tedious and error-prone, but the codemod can automate 9 deterministic transformations with 100% accuracy. The codemod is implemented in TypeScript and can be used as a standalone Node.js library. It has been validated against a production program IDL and can be used to migrate hundreds of production programs on Solana mainnet. Developers can use this codemod to avoid the migration pain and use Anchor's new declare_program! macro and TypeScript client generator.