fastjson VS jsonparser

I’ve used fastjson when unmarshalling to Structs is inconvenient. https://github.com/valyala/fastjson

Interesting approach, even though reflection support is supposed to be landing soon, this would be really really useful when using TinyGo. (Fro example, writing web backend serverless functions with Fermyon’s Spin framework for WASM that needs to return JSON). Do you have any benchmarks on how it performs vs stdlib’s encoding/json and/or something like fastjson?

It relies heavily on bytes.IndexOf for which Go provides SIMD optimizations transparently. However, it has some correctness issues when parsing malformed json that might need to be addressed. Generally it is recommended to be used with trusted json documents for internal services and may require further testing before being used to parse arbitrary json documents.

Try fastjson library. It allows you to grab deeply nested json objects without marshalling the entire json.

Como herramientas te recomiendo: FastJson https://github.com/valyala/fastjson : Si necesitas leer jsons Testify https://github.com/stretchr/testify : Para mockear y testear

In Go if I need to extract just a few fields from a large JSON document it's hard to beat https://github.com/valyala/fastjson

Another option is to use what I like to call "Lazy" decoders, like https://github.com/valyala/fastjson which will work with TinyGo, but doesn't have the same type of API as the standard lib (or alternatives) in terms of Marshaling and Unmarshalling. Instead you "Parse" a JSON object, and use Getters to access the types you want.

In this article, I will introduce you to a new package called astjson that I have been working on for the last couple of weeks. It is a Go package that allows you to transform and merge JSON objects with unmatched speed. It is based on the jsonparser package by buger aka Leonid Bugaev and extends it with the ability to transform and merge JSON objects at unparalleled performance.

Use this to extract the data value, and handle/unmarshal it accordingly.

jsonparser can decode, but can't encode

Best I've found is this: https://github.com/buger/jsonparser

I was actually just trying to get it into a []byte to use this package which claims it works well for unknown data structures.

`jj` is a little tool I wrote that uses https://github.com/buger/jsonparser

If you don't know the schema or you only need to access one or two fields in a much larger JSON object, I would recommend https://github.com/buger/jsonparser as it provides an easy API to access specific values without fully unmarshaling. This is an unusual use case though, 9 times out of 10 I would tend to use easyjson.

Reading and navigating arbitrary JSON: I've used https://github.com/tidwall/gjson, many others like https://github.com/buger/jsonparser are also out there.