React CSV Importer

This library combines an uploader + CSV parser + raw file preview + UI for custom user column mapping, all in one. It wraps the popular PapaParse CSV library to preview and process file contents directly in-browser.

Use this to implement the following bulk data import story in your app:

• 📤 user drag-drops (or selects) a file for upload
• 👓 previews the raw uploaded data before parsing
• ✏ picks which columns to import

Your front-end code will receive parsed CSV data as a series of JSON objects. You can then validate and send the data to the backend in any final format it may require instead of raw CSV. Parsing is async-enabled, so your logic can take its time: meanwhile, the user will see an animated progress bar.

Try the live editable code sandbox or see the themed demo app.

Feature summary:

• wraps the well-known Papa Parse CSV library
• raw file preview
• user-selectable column mapping (drag-drop UI)
• auto-map fields to matching column names
• TypeScript support
• screen reader a11y
• keyboard a11y
• i18n

Enterprise-level data file handling:

• 1GB+ CSV file size (true streaming support without crashing browser)
• automatically strip leading BOM character in data
• fixes a multibyte streaming issue in PapaParse
• runs entirely in-browser
• async parsing logic (pauses while your app makes backend updates)

The UI theme CSS is standalone (no external dependencies such as Material UI) and tailored to universally fit within most application design frameworks. Interface elements are tested for screen reader accessibility and keyboard-only usage (yes, actually!).

Install

# using NPM
npm install --save react-csv-importer

# using Yarn
yarn add react-csv-importer

This package is easy to fork with your own customizations, and you can use your fork directly as a Git dependency in any of your projects, see below.

Example Usage

import { Importer, ImporterField } from 'react-csv-importer';

// include the widget CSS file whichever way your bundler supports it
import 'react-csv-importer/dist/index.css';

// in your component code:
<Importer
  assumeNoHeaders={false} // optional, keeps "data has headers" checkbox off by default
  restartable={false} // optional, lets user choose to upload another file when import is complete
  onStart={({ file, preview, fields, columnFields }) => {
    // optional, invoked when user has mapped columns and started import
    prepMyAppForIncomingData();
  }}
  processChunk={async (rows, { startIndex }) => {
    // required, may be called several times
    // receives a list of parsed objects based on defined fields and user column mapping;
    // (if this callback returns a promise, the widget will wait for it before parsing more data)
    for (row of rows) {
      await myAppMethod(row);
    }
  }}
  onComplete={({ file, preview, fields, columnFields }) => {
    // optional, invoked right after import is done (but user did not dismiss/reset the widget yet)
    showMyAppToastNotification();
  }}
  onClose={({ file, preview, fields, columnFields }) => {
    // optional, if this is specified the user will see a "Finish" button after import is done,
    // which will call this when clicked
    goToMyAppNextPage();
  }}

  // CSV options passed directly to PapaParse if specified:
  // delimiter={...}
  // newline={...}
  // quoteChar={...}
  // escapeChar={...}
  // comments={...}
  // skipEmptyLines={...}
  // delimitersToGuess={...}
  // chunkSize={...} // defaults to 10000
  // encoding={...} // defaults to utf-8, see FileReader API
>
  <ImporterField name="name" label="Name" />
  <ImporterField name="email" label="Email" />
  <ImporterField name="dob" label="Date of Birth" optional />
  <ImporterField name="postalCode" label="Postal Code" optional />
</Importer>;

In the above example, if the user uploads a CSV file with column headers "Name", "Email" and so on, the columns will be automatically matched to fields with same labels. If any of the headers do not match, the user will have an opportunity to manually remap columns to the defined fields.

The preview object available to some callbacks above contains a snippet of CSV file information (only the first portion of the file is read, not the entire thing). The structure is:

{
  rawData: '...', // raw string contents of first file chunk
  columns: [ // array of preview columns, e.g.:
    { index: 0, header: 'Date', values: [ '2020-09-20', '2020-09-25' ] },
    { index: 1, header: 'Name', values: [ 'Alice', 'Bob' ] }
  ],
  skipHeaders: false, // true when user selected that data has no headers
  parseWarning: undefined, // any non-blocking warning object produced by Papa Parse
}

Importer component children may be defined as a render-prop function that receives an object with preview and file fields (see above). It can then, for example, dynamically return different fields depending which headers are present in the CSV.

Dependencies

• Papa Parse for CSV parsing
• react-dropzone for file upload
• react-use-gesture for drag-and-drop

Internationalization (i18n) and Localization (l10n)

You can swap the text used in the UI to a different locale.

import { Importer, deDE } from 'react-csv-importer';

// provide the locale to main UI
<Importer
  locale={deDE}
  // normal props, etc
/>

You can also pass your own fully custom locale definition as the locale value. See ImporterLocale interface in src/locale for the full definition, and use an existing locale like enUS as basis. For better performance, please ensure that the value is stable (i.e. does not change on every render).

Local Development

Perform local git clone, etc. Then ensure modules are installed:

yarn

To start Storybook to have a hot-reloaded local sandbox:

yarn storybook

To run the end-to-end test suite:

yarn test

You can use your own fork of this library in your own project by referencing the forked repo as a Git dependency. NPM will then run the prepare script, which runs the same Webpack/dist command as when the NPM package is published, so your custom dependency should work just as conveniently as the stock NPM version. Of course if your custom fixes could be useful to the rest of us then please submit a PR to this repo!

Changes

• 0.7.1
  • fix peerDependencies for React 18+
  • hide Finish button by default
  • button label tweaks
• 0.7.0
  • add i18n
• 0.6.0
  • improve multibyte stream parsing safety
  • support all browser encodings via TextDecoder
  • remove readable-web-to-node-stream dependency
  • bug fix for preview of short no-EOL files
• 0.5.2
  • update readable-web-to-node-stream to have stream shim
  • use npm prepare script for easier fork installs
• 0.5.1
  • correctly use custom Papa Parse config for the main processing stream
  • drag-drop fixes on scrolled pages
  • bug fixes for older Safari, mobile issues
• 0.5.0
  • report file preview to callbacks and render-prop
  • report startIndex in processChunk callback
• 0.4.1
  • clearer error display
  • add more information about ongoing import
• 0.4.0
  • auto-assign column headers
• 0.3.0
  • allow passing PapaParse config options
• 0.2.3
  • tweak TS compilation targets
  • live editable sandbox link in docs
• 0.2.2
  • empty file checks
  • fix up package metadata
  • extra docs
• 0.2.1
  • update index.d.ts generation
• 0.2.0
  • bundling core package using Webpack
  • added source maps
• 0.1.0
  • first beta release
  • true streaming support using shim for PapaParse
  • lifecycle hooks receive info about the import

Credits

Translations contributed by: @tstehr and @Valodim.