Immer 'undefined' Playground

//const immer = require('immer@8.0.1'); const immer = require('immer@9.0.2'); immer.setUseProxies(true); const state = {}; const newState = immer.produce(state, draft => { draft.baz = undefined; }); // output: // @8.0.1: false // @9.0.2: false console.log(state === newState); // output: // @8.0.1: {baz: undefined} // @9.0.2: {} console.log(newState);