Complete NDJSON example
Input consists of one JSON object per LF-terminated record. Install PocketCsvReader.Ndjson.
using System.Text;
using PocketCsvReader.Ndjson.Configuration;
var ndjson = new NdjsonReaderBuilder().WithDialect(d => d.WithLineTerminator("\n")).Build();
using var stream = new MemoryStream(Encoding.UTF8.GetBytes(
"{\"event\":\"accepted\",\"id\":1}\n{\"id\":2,\"event\":\"pending\"}\n"));
using var reader = ndjson.ToDataReader(stream);
while (reader.Read())
Console.WriteLine($"{reader.GetInt32(reader.GetOrdinal("id"))}: {reader.GetString(reader.GetOrdinal("event"))}");
1: accepted
2: pending
Newline-delimited JSON
Install PocketCsvReader.Ndjson when the input contains a sequence of complete JSON values separated by line terminators:
dotnet add package PocketCsvReader.Ndjson
using PocketCsvReader.Ndjson;
using var reader = new NdjsonReader().ToDataReader("events.ndjson");
while (reader.Read())
{
var eventName = reader.GetString(reader.GetOrdinal("event"));
}
NDJSON keeps its format-specific framing options, including custom line terminators, blank-line handling, and optional comments. Use PocketCsvReader.Json for a pretty-printed array document; use PocketCsvReader.Ndjson for independently framed JSON values.
NDJSON also supports order-independent projection:
using PocketCsvReader.Ndjson.Configuration;
var ndjson = new NdjsonReaderBuilder()
.WithProjection(projection => projection
.Property("event")
.Property("timestamp"))
.Build();
using var reader = ndjson.ToDataReader("events.ndjson");
Each NDJSON record must be a JSON object containing every projected property. Additional properties may appear anywhere and remain fully validated. Projection does not change custom line terminators, blank-line handling, or comment behavior.
When the selected properties have a guaranteed input order, WithOrderedProjection provides the same stricter contract as the JSON reader:
var ndjson = new NdjsonReaderBuilder()
.WithOrderedProjection(projection => projection
.Property("event")
.Property("timestamp"))
.Build();
Unselected properties may occur before, after, or between selected properties, but the selected properties themselves must occur in configuration order. A reordered selected property is rejected.
Both projection modes avoid representing unused fields; ordered projection also avoids the general name lookup used to find selected fields. Neither skips reading or validating the rest of the record. See Why projection improves performance for a comparison with unprojected reading and guidance on when the difference matters.
For trusted stable structure, see stable object shapes, including same-count rename/reorder risks.
Boundaries and values
Install the package shown above; the builder namespace is PocketCsvReader.Ndjson.Configuration. Configure .WithDialect(d => d.WithLineTerminator("\n")) for LF input or the appropriate explicit terminator for your producer. A final complete value need not end in a terminator. Blank-line/comment handling follows the NDJSON dialect; invalid JSON remains an error. The JSON reader’s WithJsonc() is not an NDJSON mode.
JSON null, quoted strings, numbers, arrays and nested objects retain their source semantics. Strings are decoded lazily when requested; skipped fields do not require ordinary getter string materialization. Use optional labels for changing object shapes, output models for results, and source positions for diagnostics.
Select nested nodes as records
See Select JSON nodes as rows for the supported path subset and per-record buffering. See projection and stable shapes for performance, contracts, eligibility, and fallback behavior.
