Working with TSV in TypeScript

Updated May 9, 2026

Tab-separated values (TSV) file handling with automatic format detection and high-performance data operations.

Installation

npm install fairspec

Getting Started

The TSV format is handled by the CSV plugin, which provides:

loadCsvTable - Load TSV files into tables
saveCsvTable - Save tables to TSV files
CsvPlugin - Plugin for framework integration

For example:

import { loadCsvTable } from "fairspec"

const table = await loadCsvTable({ data: "table.tsv" })
// the column types will be automatically inferred

Basic Usage

Loading TSV Files

import { loadCsvTable } from "fairspec"

// Load a simple TSV file
const table = await loadCsvTable({ data: "data.tsv" })

// Load with explicit format
const table = await loadCsvTable({
  data: "data.tsv",
  format: {
    name: "tsv",
    headerRows: [1],
  },
})

// Load multiple TSV files (concatenated)
const table = await loadCsvTable({
  data: ["part1.tsv", "part2.tsv", "part3.tsv"],
})

Saving TSV Files

import { saveCsvTable } from "fairspec"

// Save with default options
await saveCsvTable(table, {
  path: "output.tsv",
  format: { name: "tsv" },
})

// Save with line terminator option
await saveCsvTable(table, {
  path: "output.tsv",
  format: {
    name: "tsv",
    lineTerminator: "\r\n",
  },
})

Advanced Features

Multi-Header Row Processing

// TSV with multiple header rows
const table = await loadCsvTable({
  data: "multi-header.tsv",
  format: {
    name: "tsv",
    headerRows: [1, 2],
    headerJoin: "_",
  },
})

Comment Handling

// TSV with comment lines
const table = await loadCsvTable({
  data: "with-comments.tsv",
  format: {
    name: "tsv",
    commentPrefix: "#",
    headerRows: [1],
  },
})

// Or specify specific comment row numbers
const table = await loadCsvTable({
  data: "with-comments.tsv",
  format: {
    name: "tsv",
    commentRows: [1, 2],
    headerRows: [3],
  },
})

Remote File Loading

// Load from URL
const table = await loadCsvTable({
  data: "https://example.com/data.tsv",
})

// Load multiple remote files
const table = await loadCsvTable({
  data: [
    "https://api.example.com/data-2023.tsv",
    "https://api.example.com/data-2024.tsv",
  ],
})

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