[anonytrary]

It would be much nicer for the consumer to just de-dupe the keys in your json than to serve an annoying format like CSV. Your JSON could basically be a matrix with a header row, there's nothing forcing you to duplicate keys.

  { header: [...columnNames], rows: [...values2DArray]}

[earthboundkid]

Make rows 1 dimensional. You don’t need the second dimension, it’s implied by header length. Once you do this, the JSON gzips down to about the same size as CSV, according to the last time I tested this IIRC.

[anonytrary]

I edited-in the "2DArray" because I thought it was confusing... But you're right, just calculate offsets. The dominating term is still quadratic, and the term you mentioned is linear. It could be worth it for a scaled org like Google!

I wonder which parses faster. I guess CSV does but then the consuming code would still have to parse the strings into JS primitives...

[earthboundkid]

I haven't tested this, but my guess is that because the browser built in JSON.parse will be faster than whatever CSV parser you can write in JS just because it's precompiled to native code. Then the question becomes how long does it take to do the unpacking loop, but it should be pretty quick.

I'd love it if someone did a benchmark though.

[dragonwriter]

Heck, you could do a single 1-D list (no object), and just give the header count as the first element, which would be even more compact.

[earthboundkid]

Smart idea.