jpp

Fast, no-allocation, streaming, compact JSON pretty-printing CLI.

echo '{"array":[1,2,3],"boolean":true,"color":"gold","null":null,"number":123,"object":{"a":"b","c":"d"},"string":"Hello World"}' | jpp

# prints
{
  "array": [1, 2, 3],
  "boolean": true,
  "color": "gold",
  "null": null,
  "number": 123,
  "object": {"a": "b", "c": "d"},
  "string": "Hello World"
}

Building

Clone the repo and run zig build -Drelease-safe=true.

The fast build isn’t much faster, to stream a 180 MB file into a new file takes 3.2 seconds in safe mode, and 2.75 in fast mode.

Why?

I often use jq just for pretty-printing, but it prints too sparsely by default.

And it was a fun to do compact printing with the limitation of not holding the entire input in memory.