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In C++, a JavaScript object is just a piece of memory with no type. C++ doesn’t know how many and what values are in this memory. In JavaScript, these values can change dynamically, so how can C++ know the latest type in order to maintain a JavaScript. V8 updates the latest addressing method into the JavasCript object’s map in time once its type changes. In this way, JavaScript developers can alter the object type freely. The technology behind the dynamic features is powered by C++.