It&#x27;s weird to me to see this upvoted on HN.<p>1. I doubt most people here are using (or have used) asm.js, let alone memory growth.<p>2. Maybe people think some major feature is being removed from asm.js (not really, will expand below).<p>3. Maybe people are confusing asm.js with WebAssembly?<p>4. This will be in Web Assembly, see post&#x27;s point #2.<p>Emscripten-emitted-code has a fixed size memory space (static memory, stack, heap).  Heap size can grow, via sbrk, but if you moved the program break past the end of the Typed Array the code used as memory space, Emscripten could create a new Typed Array, copy over all data from the old to the new, free the old, and continue executing with data in the new.  That process was memory growth, and was very slow.  In practice, you never really needed it, since you could run your program a few times, see what the high water mark of your heap was, then set the precise size at compile time.<p>Memory growth was helpful if you wanted to start up faster, but could potentially have non-deterministic memory growth (though you&#x27;d still be limited to 32b address space).