json-as/assembly/util/idofd.ts

The only JSON library you'll need for AssemblyScript. SIMD enabled

import { OBJECT, TOTAL_OVERHEAD } from "rt/common";

// @ts-ignore: decorator
@inline export function idofD<T>(value: T): usize {
  return changetype<OBJECT>(changetype<usize>(value) - TOTAL_OVERHEAD).rtId;
}