2055774 - JSON Viewer: support JSON Lines (JSONL/NDJSON) documents

Status: RESOLVED FIXED

(DevTools :: JSON Viewer, enhancement, P3)

Description

[Benoit]

The JSON Viewer currently only handles application/json. This adds support for JSON Lines documents (one JSON value per line) served as application/jsonlines / application/x-ndjson, or as .jsonl files.

• Sniff JSONL/NDJSON content and register the stream converter (Sniffer.sys.mjs, converter-child.js, components.conf), exposing JSONView.isJsonl.
• Parse the document line-by-line into ordered, independently collapsible entries keyed by real file line number (blank lines skipped), via parseJsonl in json-viewer.mjs and jsonl-utils.mjs.
• Render lines that aren't valid JSON as inline errors (JsonlLineError) without blocking the rest of the document (JsonPanel.mjs).
• Restore the original content type on Save-As, plus docs and browser-chrome test coverage in browser_jsonview_jsonl.js.

Comment 1

[Benoit]

Attachment: Bug 2055774 - Detect JSONL/NDJSON content and register its stream converter in the JSON Viewer r=#devtools-reviewers

Comment 2

[Benoit]

Attachment: Bug 2055774 - Parse JSON Lines documents line-by-line in the JSON Viewer r=#devtools-reviewers

Comment 3

[Benoit]

Attachment: Bug 2055774 - Render invalid JSONL lines as inline errors in the JSON Viewer r=#devtools-reviewers

Comment 4

[Benoit]

Attachment: Bug 2055774 - Document JSON Viewer JSONL support r=#devtools-reviewers

Comment 5

[Nicolas Chevobbe [:nchevobbe]]

Hello Benoit, thanks for filing the bug
I guess it has the same goal as Bug 1418633 ?

Comment 6

[Benoit]

(In reply to Nicolas Chevobbe [:nchevobbe] from comment #5)

Hello Benoit, thanks for filing the bug
I guess it has the same goal as Bug 1418633 ?

No. It addresses a different type of data/file format: json lines (.jsonl)

Comment 7

[Oriol Brufau [:Oriol]]

You need to handle pretty print, e.g. data:application/jsonlines,[1,2,3]%0A{"foo":"bar"} becomes

{
  "1": [
    1,
    2,
    3
  ],
  "2": {
    "foo": "bar"
  }
}

Comment 8

[Oriol Brufau [:Oriol]]

(In reply to Nicolas Chevobbe [:nchevobbe] from comment #5)

I guess it has the same goal as Bug 1418633 ?

Actually it's the same as bug 1603986.

Comment 9

[Benoit]

(In reply to Oriol Brufau [:Oriol] from comment #8)

(In reply to Nicolas Chevobbe [:nchevobbe] from comment #5)

I guess it has the same goal as Bug 1418633 ?

Actually it's the same as bug 1603986.

It does also cover that format indeed.

Comment 10

[Benoit]

Attachment: Screenshot 2026-07-20 at 09.22.40.png

Comment 11

[Benoit]

(In reply to Oriol Brufau [:Oriol] from comment #7)

You need to handle pretty print, e.g. data:application/jsonlines,[1,2,3]%0A{"foo":"bar"} becomes

{
  "1": [
    1,
    2,
    3
  ],
  "2": {
    "foo": "bar"
  }
}

I am not sure I understand. Currently it displays the example provided as in Screenshot 2026-07-20 at 09.22.40.png

Comment 12

[Oriol Brufau [:Oriol]]

Go to Raw Data, then use Pretty Print.

Comment 13

[Benoit]

Attachment: Bug 2055774 - Hide the Pretty Print button for JSONL documents in the JSON Viewer r=#devtools-reviewers

Comment 14

[Benoit]

(In reply to Benoit from comment #11)

(In reply to Oriol Brufau [:Oriol] from comment #7)

You need to handle pretty print, e.g. data:application/jsonlines,[1,2,3]%0A{"foo":"bar"} becomes

{
  "1": [
    1,
    2,
    3
  ],
  "2": {
    "foo": "bar"
  }
}

I am not sure I understand. Currently it displays the example provided as in Screenshot 2026-07-20 at 09.22.40.png

it now handles pretty print correctly

Comment 15

[Benoit]

Attachment: Screenshot 2026-07-28 at 14.46.02.png

Comment 16

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/a4e1189c40c6
https://hg.mozilla.org/integration/autoland/rev/14f9cf3dc34d
Detect JSONL/NDJSON content and register its stream converter in the JSON Viewer r=devtools-reviewers,nchevobbe
https://github.com/mozilla-firefox/firefox/commit/fa581ca58fc1
https://hg.mozilla.org/integration/autoland/rev/d74e288e47e9
Parse JSON Lines documents line-by-line in the JSON Viewer r=devtools-reviewers,nchevobbe
https://github.com/mozilla-firefox/firefox/commit/73a45282103f
https://hg.mozilla.org/integration/autoland/rev/aee51b0ff455
Render invalid JSONL lines as inline errors in the JSON Viewer r=devtools-reviewers,nchevobbe
https://github.com/mozilla-firefox/firefox/commit/db1301d2bc20
https://hg.mozilla.org/integration/autoland/rev/75b28caf059f
Document JSON Viewer JSONL support r=devtools-reviewers,nchevobbe
https://github.com/mozilla-firefox/firefox/commit/85799112a910
https://hg.mozilla.org/integration/autoland/rev/cba8d07f81c4
Hide the Pretty Print button for JSONL documents in the JSON Viewer r=devtools-reviewers,nchevobbe

Comment 17

[amarc]

https://hg.mozilla.org/mozilla-central/rev/14f9cf3dc34d
https://hg.mozilla.org/mozilla-central/rev/d74e288e47e9
https://hg.mozilla.org/mozilla-central/rev/aee51b0ff455
https://hg.mozilla.org/mozilla-central/rev/75b28caf059f
https://hg.mozilla.org/mozilla-central/rev/cba8d07f81c4

Comment 19

[Ryan VanderMeulen [:RyanVM]]

Did you want to nominate this for the Fx155 relnotes? If so, set the relnote-firefox flag to "?"
https://wiki.mozilla.org/Release_Management/Release_Notes_Nomination

Possible wording:

The JSON Viewer now displays JSON Lines (JSONL/NDJSON) documents, including inline errors for invalid lines.

Comment 20

[Nicolas Chevobbe [:nchevobbe]]

Release Note Request (optional, but appreciated)
[Why is this notable]:
[Affects Firefox for Android]:
[Suggested wording]:
[Links (documentation, blog post, etc)]:

(In reply to Ryan VanderMeulen [:RyanVM] from comment #19)

Did you want to nominate this for the Fx155 relnotes? If so, set the relnote-firefox flag to "?"
https://wiki.mozilla.org/Release_Management/Release_Notes_Nomination

Sure

Possible wording:

The JSON Viewer now displays JSON Lines (JSONL/NDJSON) documents, including inline errors for invalid lines.

Yeah, looks good to me, thanks!

Comment 21

[Ryan VanderMeulen [:RyanVM]]

Added to the Fx155 relnotes.