TOON to Table ViewerTOON to Table

Why TOON reads so naturally as a table

Most format viewers have to invent a table. Given nested JSON they guess which array is the interesting one, flatten what is underneath it, and hope the columns make sense. With TOON there is nothing to guess: a tabular block already is a table. The header line subscribers[4]{subscriberId,msisdn,iccid,plan,roaming,rsrp}: names the columns and states the row count, and the indented lines beneath it are the rows.

So this page is less a converter than a renderer. The header becomes the column row, each delimited line becomes a record, and sorting and filtering work the way you would expect. Where a document has nested blocks rather than tabular ones — a cell: section holding cellId and tac, say — those are flattened into dotted column names so nothing is hidden from you.

That closeness to a grid is the practical argument for the format. A tabular block is roughly what you would get from RFC 4180 CSV, except that it can also express the nested sections CSV has no way to represent, and it carries its own row count so a truncated file is detected rather than quietly accepted.

The format is defined by a public specification and reference implementation, which is worth a look if you are deciding whether to adopt it. It is still at 0.x.

Reading a document here

1. Paste your TOON – Left pane, or press Sample to see a populated table immediately. The grid rebuilds as you type, so a malformed row can be fixed in place.
2. Sort and filter – Click a column header to sort. The filter box narrows rows across every column at once, which is the quickest way to find one subscriber in a few thousand.
3. Drop columns you do not care about – Wide exports are easier to read with the noise removed. Removing a column here only affects the view.
4. Maximize for a wide document – Maximize gives the grid the full window, which is usually the difference between scrolling sideways and not.
5. Save a link if you want to come back – Save stores the document and hands you a URL that reopens it. Anything you do not save stays in this tab and nowhere else.

If the table comes back with one row and a column called value, your document is a single scalar or a list of scalars rather than records. TOON only produces a tabular block when every object in an array carries the same fields — the same uniformity that JSON to Table needs, for the same reason.

A header line and what it becomes

Four subscriber records. Read the header once and you already know the shape of the grid on the right.

subscribers[3]{msisdn,imsi,plan,roaming,rsrp}:
  "447700900142","234150999912345",Unlimited 5G,true,-92
  "447700900458","234150999967810",Pay As You Go,false,-104
  "447700900773","234150999934562",Business 200GB,true,-78

When you would reach for this

Checking an export before it goes anywhere

A dense block of comma-separated rows hides an empty field or a shifted column extremely well. Put it in a grid and a blank cell is obvious at a glance. This is the fastest sanity check there is on a file someone just handed you.

Finding the outlier

Sort by rsrp and the worst cell in the export is the first row. Sort by iccid and duplicates sit next to each other. Neither question is answerable by reading the raw text.

Explaining a file to someone else

Handing a colleague a screenshot of a grid works. Handing them a wall of delimited rows and a header they have to parse in their head does not.

Deciding whether TOON suits your data at all

If your document renders as one clean table, TOON is a good fit and converting from JSON will pay off. If it renders as a handful of loose rows with mostly empty columns, your data is not uniform enough to benefit and you are better off leaving it as JSON.

Questions people actually ask

Why does my long ID look right here but wrong everywhere else?

Because most readers hand the value to JavaScript, which cannot hold an integer past Number.MAX_SAFE_INTEGER — every number is a double, as ECMA-262 defines the Number type. An ICCID of 8901240544102066246 comes back as 8901240544102066000, and the SIM one digit along collapses onto the same value. This page reads those digits before that can happen, so what you see in the cell is what is in the file.

Can I put comments in my TOON?

No, and this catches people coming from YAML almost immediately. There is no comment syntax — a line starting with # fails with Missing colon after key, because the reader is trying to interpret it as a key. If you need to annotate a document, the annotation has to become a field.

My file uses tabs between values. Is that allowed?

Yes. Comma, tab and pipe are all legal, and the header records which one the document uses. That is also why this editor inserts spaces when you press Tab — a stray tab in a row would change where the fields split rather than just indenting oddly.

It rejected my file over the row count.

The number in the header is a promise about how many rows follow, and it is enforced rather than advisory. Usually someone has added or deleted a line by hand without updating it. Annoying in the moment, but it is the check that stops a truncated download from looking like a complete one.

Can I get this as JSON or CSV instead?

Yes — TOON to JSON expands it into objects, and from there JSON to CSV takes it to a spreadsheet. If you are moving data between systems rather than reading it, JSON Lines is worth considering too, since almost everything already reads it.

Does anything get uploaded?

Only if you press Save, which exists to create a shareable link and is the one action that stores anything. Pasting, sorting, filtering and downloading all happen in this tab.

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