Frida ObjC.Block example

example.js

const pendingBlocks = new Set();

Interceptor.attach(..., {
  onEnter(args) {
    const block = new ObjC.Block(args[4]);
    pendingBlocks.add(block); // Keep it alive
    const appCallback = block.implementation;
    block.implementation = (success, error) => {
      // Do your logging here
      appCallback(success, error);
      pendingBlocks.delete(block);
    };
  }
});

nice work!