Suggested perf improvement for high-scale icon rendering

[leahand]

Environment

• Package version(s): blueprint-core 5.3.0 / blueprint-icons 5.1.6
• Browser and OS versions: macos / chrome 117.0.5938.88

Feature request

Medium-to-high-scale lists with <Icon /> components in each list item spend a disproportionate amount of time validating icon name validity via IconLoader.isValidIconName. For example, mounting a list of <100 items spends 1-2ms in this validation function alone.

https://github.com/palantir/blueprint/blob/develop/packages/icons/src/iconLoader.ts#L141

It seems like a more efficient storage/memoization of the icon name strings to avoid repeated re-creation of the IconNames.values() array would be a reasonable low-lift FR that could make a notable difference here.

Examples