Equivalent ImmutableJS object seems to have high memory usage

[Methuselah96]

From @NMagno on Tue, 17 Dec 2019 07:41:25 GMT

What happened

Creating a large list of small maps seems to have poor memory performance.

How to reproduce

JSfiddle demonstrating the issue. As you can see, the memory usage when making the equivalent list of small maps is significantly larger.

In this image, you see that Immutable is taking about 5x memory usage as the standard JS array.

Copied from original issue: immutable-js#1754