This is a non-argument. Firstly, JS does indeed have typed arrays and other tools for managing memory. More importantly, unless you're doing 3D or similar it's

This is a non-argument. Firstly, JS does indeed have typed arrays and other tools for managing memory. More importantly, unless you're doing 3D or similar it's vanishingly rare that the memory used by objects you've allocated in JS will be measurable compared to the memory used for DOM objects and rendering generally. Replacing JS with some other language wouldn't affect the memory usage of typical web pages.