Parsing CSV and TSV

Lanexio Parser handles CSV and TSV through a single package with configurable parsing. Both formats use the same never-throw parse path and produce zero-copy flat ASTs.

Quick start

1. Install the package.

   pnpm

   pnpm add @lanexio/parser-grammar-csv

   npm

   npm install @lanexio/parser-grammar-csv

   yarn

   yarn add @lanexio/parser-grammar-csv

2. Parse a CSV file.

   import { parseCsv } from '@lanexio/parser-grammar-csv';
   
   const encoder = new TextEncoder();
   const tree = parseCsv(encoder.encode('Name,Age,City\nAlice,30,NYC\nBob,25,LA'));

3. Parse with options.

   import { parseCsv } from '@lanexio/parser-grammar-csv';
   
   const tree = parseCsv(encoder.encode('Name|Age|City\nAlice|30|NYC'), {
     delimiter: '|',
     header: true,
   });

TSV files

import { parseTsv } from '@lanexio/parser-grammar-csv';

const tree = parseTsv(encoder.encode('Name\tAge\tCity\nAlice\t30\tNYC'));

Options

Option	Type	Default	Description
delimiter	string	','	Field delimiter character
quote	string	'"'	Quote character for field escaping
header	boolean	false	Whether the first record is a header row
skipEmptyLines	boolean	false	Whether to skip empty lines

Inspecting the tree

Each record is a CsvRecord node containing CsvField children. Fields in the header row carry CSV_FLAG_HEADER; quoted fields carry CSV_FLAG_QUOTED.

const cursor = tree.cursor();
cursor.gotoFirstChild(); // CsvRecord (first row)
cursor.gotoFirstChild(); // CsvField
console.log(cursor.current.kind);   // CsvField kind id
console.log(cursor.current.flags);  // CSV_FLAG_HEADER | CSV_FLAG_QUOTED

See also

• CSV reference page
• CSV conformance