[RaphaelFakhri]

Summary

SvgUri decodes data:image/svg+xml;base64,... URIs with atob, which returns one character per byte. Since #2808 (15.15.3), any SVG with non-ASCII text in a base64 data URI renders garbled: Café becomes Café. Before #2808, Buffer.from(content, 'base64').toString('utf-8') decoded the bytes as UTF-8.

This change keeps atob (no buffer dependency) and decodes its output as UTF-8 by percent-encoding each byte and passing the result to decodeURIComponent. If the bytes are not valid UTF-8, it returns the atob output unchanged, which matches the current behavior.

It only affects fetchText in src/utils/fetchData.ts, used by SvgUri, SvgCssUri, and SvgFromUri.

Test Plan

Added __tests__/fetchData.test.ts, which decodes an ASCII and a UTF-8 (Café © 日本 😀) base64 data URI.

npx jest __tests__/fetchData.test.ts --globalSetup <no-op> --globalTeardown <no-op>

• Without the fix: 1 failed, 1 passed. The UTF-8 case receives Café © æ¥æ¬ ð.
• With the fix: 2 passed.

yarn lint and yarn tsc report nothing new.

What's required for testing (prerequisites)?

An app that renders SvgUri with a base64 data URI whose SVG contains non-ASCII text.

What are the steps to reproduce (after prerequisites)?

1. Render <SvgUri uri="data:image/svg+xml;base64,..." /> where the SVG contains <text>Café</text>.
2. Without the fix, the text reads Café. With the fix, it reads Café.

Compatibility

OS	Implemented
iOS	✅
MacOS	✅
Android	✅
Web	✅

Checklist

• I have tested this on a device and a simulator
• I added documentation in README.md
• I updated the typed files (typescript)
• I added a test for the API in the __tests__ folder

Fixes #3092