json_query library

Extract and map fields from deeply nested JSON into Dart models without writing repetitive manual traversal code.

Classes

CompiledQuery: A projection parsed once and reusable across many JSON payloads, avoiding repeated path parsing for queries executed in a loop or on a hot path.
FieldSegment: .name — read a field from a Map.
IndexSegment: [n] — read an index from a List.
JsonQuery: Wraps a decoded JSON value (Map, List, or any dynamic) and lets you pull out exactly the fields you need using small jq-inspired path strings, optionally mapping the result straight into a Dart object.
PathSegment: One step in a parsed query path. A path string is parsed directly into a List<PathSegment> — that list is the compiled query, there is no separate AST/compiler stage.
WildcardSegment: [] — apply the remaining segments to every element of a List.

parsePath(String path) → List<PathSegment>: Parses a jq-inspired path string (e.g. .data.user.id, .data.users[0], .data.users[]) into a list of PathSegments by walking characters directly — no regex, no intermediate string splitting.

JsonQueryAccessException: A path was well-formed but could not be resolved against the given JSON while required: true was set (wrong type at a segment, missing field, index out of range).
JsonQueryException: Base type for all exceptions thrown by json_query.
JsonQuerySyntaxException: A query path string could not be parsed (bad syntax, empty segment, invalid array index, etc).