Symbol.iterator polyfill in ecmascript-runtime-client breaks native iterator protocol on the client Versions Meteor : METEOR@3.4 ecmascript-runtime-client : 0.12.3 core-js (transitive, bundled): 3.47.0 @meteorjs /rspack : 1.0.2 (modern web targets only) Symptom On the client, any code that uses the native iterator protocol on a built-in iterator — for (const x of arr.entries()) , for (const [k, v] of map.entries()) , for (const v of map.values()) , etc. — can throw at runtime: TypeError: b.entries is not a function or its return value is not iterable at … in our app bundle The first part of th