handler.set() - JavaScript | MDN
The handler.set() method is a trap for the [[Set]] object internal method, which is used by operations such as using property accessors to set a property's value.| developer.mozilla.org
JavaScript's strict mode is a way to opt in to a restricted variant of JavaScript, thereby implicitly opting-out of "sloppy mode". Strict mode isn't just a subset: it intentionally has different semantics from normal code. Strict mode code and non-strict mode code can coexist, so scripts can opt into strict mode incrementally.| developer.mozilla.org
The Reflect.set() static method is like the property accessor and assignment syntax, but as a function.| developer.mozilla.org
The Object.assign() static method copies all enumerable own properties from one or more source objects to a target object. It returns the modified target object.| developer.mozilla.org
The handler.set() method is a trap for the [[Set]] object internal method, which is used by operations such as using property accessors to set a property's value.| developer.mozilla.org
