Make uniqueKey undefined by default

[mischnic]

Previously, asset.uniqueKey was an empty string by default, so import ""; would match up with the unique key and then cause this:

[parcel-benchmark]

Benchmark Results

Kitchen Sink ✅

Timings

Description	Time	Difference
Cold	1.61s	+5.00ms
Cached	352.00ms	+7.00ms

Cold Bundles

Bundle	Size	Difference	Time	Difference
dist/legacy/parcel.7cdb0fad.webp	102.94kb	+0.00b	99.00ms	-158.00ms 🚀
dist/legacy/parcel.7cdb0fad.webp	102.94kb	+0.00b	99.00ms	-159.00ms 🚀
dist/modern/parcel.7cdb0fad.webp	102.94kb	+0.00b	99.00ms	-158.00ms 🚀
dist/legacy/index.2c76ad23.js	1.66kb	+0.00b	463.00ms	+26.00ms ⚠️
dist/legacy/index.8aaa89c9.js	1.20kb	+0.00b	464.00ms	+26.00ms ⚠️
dist/modern/index.6be20f01.js	1.13kb	+0.00b	463.00ms	+26.00ms ⚠️
dist/legacy/index.b8ae99ba.css	94.00b	+0.00b	291.00ms	+27.00ms ⚠️
dist/modern/index.31cedca9.css	94.00b	+0.00b	290.00ms	+27.00ms ⚠️

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/legacy/parcel.7cdb0fad.webp	102.94kb	+0.00b	274.00ms	+178.00ms ⚠️
dist/legacy/parcel.7cdb0fad.webp	102.94kb	+0.00b	274.00ms	+177.00ms ⚠️
dist/modern/parcel.7cdb0fad.webp	102.94kb	+0.00b	275.00ms	+178.00ms ⚠️

React HackerNews ✅

Timings

Description	Time	Difference
Cold	10.53s	-88.00ms
Cached	468.00ms	-50.00ms 🚀

Cold Bundles

No bundle changes detected.

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/index.js	486.37kb	+0.00b	5.48s	-715.00ms 🚀
dist/PermalinkedComment.46b19af5.js	4.21kb	+0.00b	5.48s	-715.00ms 🚀
dist/UserProfile.f8cd7884.js	1.57kb	+0.00b	5.48s	-714.00ms 🚀
dist/NotFound.960ab92b.js	429.00b	+0.00b	5.48s	-715.00ms 🚀
dist/logo.c5bb83f1.png	246.00b	+0.00b	5.48s	-711.00ms 🚀

AtlasKit Editor ✅

Timings

Description	Time	Difference
Cold	1.87m	+671.00ms
Cached	2.53s	+253.00ms ⚠️

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

Three.js ✅

Timings

Description	Time	Difference
Cold	7.45s	+69.00ms
Cached	296.00ms	+2.00ms

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

Click here to view a detailed benchmark overview.