René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Dotted flags sharing a prefix overwrite each other (`--a.b=1 --a.c=2` yields `{ a: { c: 2 } }`)","articleBody":"### Package\n\n@bomb.sh/args\n\n### Package Version\n\nv0.3.1 (also on main `3bc34eb`)\n\n### Node.js Version\n\nv26.13.0\n\n### Operating System\n\nLinux\n\n### Describe the bug\n\nWhen multiple dotted flags share a path prefix, each subsequent flag overwrites the parent object instead of merging into it. In `set()` (`src/index.ts`), every intermediate path segment creates a fresh `const tmp = {}` and assigns `set(obj, k, tmp)` without checking whether `obj[k]` is already an object.\n\n### To Reproduce\n\nReproduction link: https://gist.github.com/trackoor/bd7f8e655e9f13ce293117d288558f53\n\n```js\n// repro.mjs (npm i @bomb.sh/args@0.3.1 && node repro.mjs)\nimport { parse } from \"@bomb.sh/args\";\n\nconsole.log(parse([\"--a.b=1\", \"--a.c=2\"]));\n// Actual: { _: [], a: { c: 2 } }\n\nconsole.log(parse([\"--a.b.c=1\", \"--a.b.d=2\", \"--a.e=3\"]));\n// Actual: { _: [], a: { e: 3 } }\n```\n\n### Expected behavior\n\nSibling nested keys under the same prefix should be preserved (matching Deno's `std/cli` `parseArgs`):\n\n```js\n// parse([\"--a.b=1\", \"--a.c=2\"])\n{ _: [], a: { b: 1, c: 2 } }\n\n// parse([\"--a.b.c=1\", \"--a.b.d=2\", \"--a.e=3\"])\n{ _: [], a: { b: { c: 1, d: 2 }, e: 3 } }\n```\n\n### Additional Information\n\nFound with a differential-testing tool; the report was drafted with AI assistance and reviewed and edited by me.\n\n### AI assistance disclosure\n\n- [x] This bug report was drafted with the assistance of an AI tool.\n\nCredit: https://ucsbplse.github.io/\n","author":{"url":"https://github.com/trackoor","@type":"Person","name":"trackoor"},"datePublished":"2026-11-14T05:12:33Z","url":"https://github.com/bombshell-dev/args/issues/19"}