json

Flattens Json values into path-keyed leaves and reconstructs them with bounded, typed validation. See the module README for consumer setup and package imports.

#Usage

Flatten a nested document for path-keyed storage, then reconstruct the original structure.

///|
test {
  let source : Json = { "users": [{ "name": "Ada" }] }
  let flattened = flatten(source, JsonPointer)
  assert_eq(flattened, { "/users/0/name": "Ada" })
  assert_eq(from_flatten_json(flattened, JsonPointer), source)
}

#Package behavior

Supports RFC 6901 JSON Pointer and JavaScript-style paths.
Expands arrays by default or preserves them as Json leaves.
Rejects conflicting paths, invalid paths, sparse arrays, and oversized paths with FlattenJsonError.

#API

Mooncakes API reference

This README was generated from the share-artifact skill and README template.

FlattenJsonError

source

pub(all) suberror FlattenJsonError {
  ObjectValue(String)
  AmbiguousPointerToken(String)
  InvalidPath(String)
  PathLengthExceeded(Int)
  PathDepthExceeded(Int)
  PathConflict(String)
  ArrayIndexGap(String)
} derive(Eq, @moonbitlang/core/debug.Debug
Debug)

A failure while decoding or reconstructing flattened JSON paths.

ArrayMode

source

pub(all) enum ArrayMode {
  Expand
  Preserve
} derive(Eq, @moonbitlang/core/debug.Debug
Debug)

Controls whether arrays are expanded into indexed paths.

PathFormat

source

pub(all) enum PathFormat {
  JsonPointer
  JavaScript
} derive(Eq, @moonbitlang/core/debug.Debug
Debug)

The string representation used for flattened JSON paths.

flatten

source

fn flatten(json : Json, format : PathFormat, array_mode? : ArrayMode) -> Map[String, Json] raise FlattenJsonError

Flattens JSON containers into path-keyed JSON leaf values.

The caller must select RFC 6901 JSON Pointer or JavaScript-style paths. Objects are traversed recursively. Arrays are expanded by default; pass array_mode=Preserve to retain each array as a single Json leaf. Primitive values and empty arrays remain Json leaves. A root empty object produces an empty map, while nested empty objects remain Json leaves. JSON Pointer also rejects object keys matching RFC 6901 array-index syntax because they cannot be distinguished from array indices during reconstruction; JavaScript paths preserve them as bracket-quoted keys.

from_flatten_json

source

fn from_flatten_json(flattened : Map[String, Json], format : PathFormat) -> Json raise FlattenJsonError

Reconstructs JSON from path-keyed leaf values.

format must match the format passed to flatten. Non-empty object values are rejected because they must be represented by their flattened children; empty objects are valid leaves. Paths longer than 16,384 UTF-16 code units or deeper than 256 segments are rejected to keep reconstruction within a bounded typed-error boundary.