In a blog post, Microsoft offered a couple of examples of its JavaScript improvements. One of them concerns how Edge handles small-sized functions in scripts on websites:

To optimize for this pattern especially in terms of memory consumption, Chakra has refactored the metadata format used for each function (internally referred to as FunctionBody). Based on data, pointers in FunctionBody that point to rarely used information have been moved to a dynamic auxiliary structure and will not be instantiated and consume memory unless necessary. A good example is the asm.js related data which is not applicable for most functions. Most of the 32-bit counters in FunctionBody were also observed to hardly have values over 256, such as the variable count or object literal count within a function. Thus these counters have been replaced by a compact structure that uses a single byte for each counter and can be promoted to full 32-bit if needed. Combined with a good number of functions, these seemingly subtle optimizations can make a big difference in reducing memory overhead.