[suraiya-ctrl]

__rest copies the remaining keys with t[p] = s[p], so an own __proto__ key on the source goes through the Object.prototype.__proto__ setter instead of becoming a property:

• const { id, ...rest } = JSON.parse('{"id":1,"__proto__":{"isAdmin":true}}') natively gives rest.isAdmin === undefined and an own __proto__ key
• downleveled through tslib, rest's prototype becomes the payload object, so rest.isAdmin === true and Object.keys(rest) is empty
• native object rest uses CreateDataProperty, so defining that one key with Object.defineProperty matches spec behavior; all other keys keep the plain assignment

Added test/node/rest.test.js, which fails on all three builds before this change and passes after. Object spread (__assign) is unchanged since it defers to Object.assign, which uses [[Set]] natively too. The emitted helper in microsoft/TypeScript would need the same change.

[suraiya-ctrl]

@microsoft-github-policy-service agree company="Digiscrypt Technologies"