3.48.0 - 2026.01.21

• Changes v3.47.0...v3.48.0 (126 commits)
• Map upsert proposal:
  • Built-ins:
    • Map.prototype.getOrInsert
    • Map.prototype.getOrInsertComputed
    • WeakMap.prototype.getOrInsert
    • WeakMap.prototype.getOrInsertComputed
  • Moved to stable ES, January 2026 TC39 meeting
  • Added es. namespace modules, /es/ and /stable/ namespaces entries
• Use CreateDataProperty / CreateDataPropertyOrThrow in some missed cases, #1497
• Minor fix / optimization in the RegExp constructor (NCG and dotAll) polyfill
• Added some more workarounds for a Safari < 13 bug with silent ignore of non-writable array .length
• Added detection of a Webkit bug: Iterator.prototype.flatMap throws on iterator without return method
• Added detection of a V8 ~ Chromium < 144 bug: Uint8Array.prototype.setFromHex throws an error on length-tracking views over ResizableArrayBuffer
• Compat data improvements:
  • Map upsert proposal features marked as shipped in V8 ~ Chrome 145
  • Joint iteration proposal features marked as shipped in FF148
  • Iterator.concat marked as shipped in Bun 1.3.7
  • Added Rhino 1.9.0 compat data
  • Added Deno 2.6 compat data mapping
  • Added Opera Android 93 and 94 compat data mapping
  • Added Electron 41 compat data mapping
  • Iterator.prototype.flatMap marked as supported from Safari 26.2 and Bun 1.2.21 because of a bug: throws on iterator without return method
  • Uint8Array.prototype.setFromHex marked as supported from V8 ~ Chromium 144 because of a bug: throws an error on length-tracking views over ResizableArrayBuffer