fix(node/buffer): fix base64 decoding for strings with hyphens#32298
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bartlomieju merged 1 commit intodenoland:mainfrom Feb 26, 2026
Merged
fix(node/buffer): fix base64 decoding for strings with hyphens#32298bartlomieju merged 1 commit intodenoland:mainfrom
bartlomieju merged 1 commit intodenoland:mainfrom
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Fixes base64 decoding for strings containing `-` and `_` characters (base64url chars). Two bugs: (1) base64url replacements happened after base64clean, causing wrong padding calculation, and (2) base64clean appended `===` for length%4==1 which is invalid base64 — now drops the trailing char like Node does. Closes denoland#24908 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Tango992
approved these changes
Feb 25, 2026
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Summary
Buffer.from(str, "base64")throwing on strings containing-characters (e.g."base64-encoded-bytes-from-browser")base64ToBytes/base64clean:-→+,_→/) were applied afterbase64clean, so the padding calculation used the wrong string lengthbase64cleanappended===whenlength % 4 == 1, which is invalid base64 padding — now drops the trailing character to match Node.js behaviorTest plan
tests/unit_node/buffer_test.tsverifying:Buffer.from("base64-encoded-bytes-from-browser", "base64")produces correct output matching Node.jsBuffer.from("not-valid-base64!!!", "base64")doesn't throwBuffer.from("A", "base64")returns empty buffer (single char too short)Closes #24908
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