A JSON Lines file (.jsonl, .ndjson) renders as a table, as CSV does #10322

.jsonl and .ndjson files now render as a table through the CSV view. The new tests and tsc pass, and scripts/gate.ts printed nothing. I did not run the full suite or open a file in a running preview.

• Kinds: both extensions are the csv kind in src/web/render/kinds.ts, so they get the same sort and filter script as CSV. src/web/render/csv.ts sends them to a new parser, src/web/render/jsonl-parse.ts.
• Columns and cells: the columns are the union of the keys of the first 1,000 objects, in first-seen order. Strings show as they are and null shows empty. Nested values show as compact JSON, escaped like every other cell.
• Bad lines: a line that is not valid JSON, or is valid JSON but not an object, becomes one row reading Line N: not valid JSON or Line N: not a JSON object. N is the physical line number, blank lines included. The rest of the file still renders.
• Edge cases: a file with no non-blank lines falls back to the source view with "The file has no rows." If no line is an object, the table has a single column called line.
• Header: it reads "N rows × M columns · JSON Lines · size".
• Tests: test/render-csv.test.ts covers mixed keys, a bad line, a <script> value arriving escaped, a non-object line and an empty file. test/render-kinds.test.ts has the two new extensions.

I did not add per-key type detection, so JSON numbers are not right-aligned the way CSV numbers are. Columns are not capped for JSONL; the cell cap still bounds the rows drawn, but a file with an enormous number of distinct keys would make a very wide header. There are no new dependencies.

To try it, open any .jsonl file in a repository on the preview. For example, three lines of {"a":1}, {"b":"<script>"} and oops give a 3-row table with a Line 3 row.

Two commits went in because the repo's pre-push hook wants a Try: line in a commit message. The first push was rejected for that, so the Try: line is in the second commit.

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Closes #10285

.jsonl and .ndjson files now render as a table through the CSV view. The new tests and tsc pass, and scripts/gate.ts printed nothing. I did not run the full suite or open a file in a running preview.

• Kinds: both extensions are the csv kind in src/web/render/kinds.ts, so they get the same sort and filter script as CSV. src/web/render/csv.ts sends them to a new parser, src/web/render/jsonl-parse.ts.
• Columns and cells: the columns are the union of the keys of the first 1,000 objects, in first-seen order. Strings show as they are and null shows empty. Nested values show as compact JSON, escaped like every other cell.
• Bad lines: a line that is not valid JSON, or is valid JSON but not an object, becomes one row reading Line N: not valid JSON or Line N: not a JSON object. N is the physical line number, blank lines included. The rest of the file still renders.
• Edge cases: a file with no non-blank lines falls back to the source view with "The file has no rows." If no line is an object, the table has a single column called line.
• Header: it reads "N rows × M columns · JSON Lines · size".
• Tests: test/render-csv.test.ts covers mixed keys, a bad line, a <script> value arriving escaped, a non-object line and an empty file. test/render-kinds.test.ts has the two new extensions.

I did not add per-key type detection, so JSON numbers are not right-aligned the way CSV numbers are. Columns are not capped for JSONL; the cell cap still bounds the rows drawn, but a file with an enormous number of distinct keys would make a very wide header. There are no new dependencies.

To try it, open any .jsonl file in a repository on the preview. For example, three lines of {"a":1}, {"b":"<script>"} and oops give a 3-row table with a Line 3 row.

Two commits went in because the repo's pre-push hook wants a Try: line in a commit message. The first push was rejected for that, so the Try: line is in the second commit.

🤖 Generated with Claude Code

All three review items are done and pushed.

• How-to: docs/features/csv-view.md has a new "JSON Lines" section. It covers the columns rule, how nested values show, the Line N: not valid JSON and Line N: not a JSON object rows, the source fallback for an empty file, and the 200-column draw limit. The README is untouched.
• Column cap: parseJsonl now builds the header and every row at no more than COLUMN_CAP (200) columns, and csv.ts passes that cap in. columns still holds the true key count, so "Showing 200 of 205 columns" still appears.
• Key-window test: a key first seen on object 1,001 is not a column. A second test with COLUMN_CAP + 5 keys checks the cap and the "Showing N of M columns" note.

bun test on test/render-csv.test.ts and test/render-kinds.test.ts passes, and tsc is clean. scripts/gate.ts printed nothing. I did not run the full suite.

The intermediate push, 07df0ca20, had a failing test of mine: it matched <th>a</th>, but numeric headers carry class="num". The last commit fixes the match, so the branch tip is green.

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JSON Lines files (.jsonl, .ndjson) now show as a table through the CSV view. Each object is one row. The columns are all the keys found in the first 1,000 objects, in the order they first appear. Nested values show as compact JSON and null shows as an empty cell. A line that doesn't parse, or isn't an object, becomes one row with its line number ("Line 3: not valid JSON"), and the rest of the file still shows. The table only builds as many columns as the page can draw, and the summary still gives the full count.

This push fixes the review finding: a row that lacked a key could show a value inherited from JavaScript objects. If one line had a key like constructor, toString or __proto__, every row without that key showed function Object() { [native code] } or {} instead of an empty cell. The cell now reads the value only when the row's own object has that key (Object.hasOwn), in src/web/render/jsonl-parse.ts:61.

The new test in test/render-csv.test.ts parses {"constructor":1,"toString":2,"__proto__":3} and then {"a":1}. It checks that the second row's first three cells are empty and that the first row keeps its own values. It fails without the fix and passes with it. bun scripts/gate.ts, bun x tsc --noEmit and bun test test/render-csv.test.ts (22 pass) all pass. I did not check the preview.

To try it, open any .jsonl or .ndjson file on a blob page. docs/features/csv-view.md has the details.

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