XLSX-Wasm-Parser

A WebAssembly wrapper over the Rust Calamine crate, bringing Blazingly Fast (🔥) XLSX deserialization for Excel-files to both the browser and NodeJS.

About

This project is designed for deserializing XLSX files in the browser and Node. It takes the bytes of a file and returns either a 2D array of cells, or a list of objects based on a passed schema, which can be validated through built-in integration with Zod.

Can I use this in production?

This project is still in it's early stages, and only implements the bare essentials for deserializing XLSX files. If all you need is to either get all rows from a file, or getting rows based on a schema, you can use this library as I won't be making breaking changes to the current public interface. However if you need full support for all XLSX features today, please consider using read-excel-file instead. If you have any feature requests, please open an issue. If you would like to contribute, please open a PR.

🚴 Usage

🐑 Install via NPM

npm install xlsx-wasm-parser

Set-up with Webpack

We need to enable experimental WASM support in Webpack. To do this, add the following to your Webpack config:

// webpack.config.js
module.exports = {
  //...
  experiments: {
    ...,
    asyncWebAssembly: true,
    topLevelAwait: true,
  },
};

Set-up with NextJS

For NextJS we need to enable WASM-support in the Webpack-bundler, which can be done by adding the following to your next.config.js-file

const config = {
  ...
  webpack: (config) => {
    // enable webassembly
    config.experiments = { ...config.experiments, asyncWebAssembly: true, topLevelAwait: true };
    return config;
  },
};

⚡ Set-up with Vite

Vite requires the vite-plugin-wasm to run WebAssembly, which in turn requires the vite-plugin-top-level-await plugin. To use this library with Vite, you must install both of these plugins and add them to your Vite config.

npm i -D vite-plugin-wasm vite-plugin-top-level-await

// vite.config.ts
import wasm from "vite-plugin-wasm";
import topLevelAwait from "vite-plugin-top-level-await";

export default defineConfig({
  plugins: [wasm(), topLevelAwait()],
});

SSR & SSG

Since the code might run on both the server and the client, we need to dynamically import the library based on the environment. This can be done by using the following code:

const { getAllRows } =
  typeof window === "undefined"
    ? await import("xlsx-wasm-parser/node")
    : await import("xlsx-wasm-parser");

🌐 Usage in the browser

Getting all rows

import { getAllRows } from "xlsx-wasm-parser";

const input = document.getElementById("input");
input.addEventListener("change", () => {
  // Currently only supports sync operations and therefore requires inputs to be of type ArrayBuffer or a Uint8Array
  input.files?.[0]?
    .arrayBuffer()
    .then((buf) => getAllRows(buf))
    .then((rows) => {
      // Rows is a 2d array of cells
    });
});

// Fetch response
fetch("https://example.com/file.xlsx")
  .then((response) => response.arrayBuffer())
  .then((buf) => getAllRows(buf))
  .then((rows) => {
    // Rows is a 2d array of cells
  });

Getting rows based on a schema

import { getParsedRows } from "xlsx-wasm-parser";

const xlsxSchema = [
  [0, "name"],
  [1, "age"],
  [2, "address"]
] as [number, string][];

const input = document.getElementById("input");
input.addEventListener("change", () => {
  // Currently only supports sync operations and therefore requires inputs to be of type ArrayBuffer or a Uint8Array
  input.files?.[0]?
    .arrayBuffer()
    .then((buffer) => getRows(buffer, xlsxSchema))
    .then((rows) => {
      // Rows is a list of objects based on the schema
    });
});

To use the validation feature, import the getParsedRowsWithZodSchema function from the validation entry-point.

With Zod Validation

import { getParsedRowsWithZodSchema} from "xlsx-wasm-parser/validation";
import z from "zod";

const xlsxSchema = [
  [0, "name"],
  [1, "age"],
  [2, "address"]
] as [number, string][];
const zodSchema = z.object({
  name: z.string(),
  age: z.number(),
  address: z.string(),
});

const input = document.getElementById("input");
input.addEventListener("change", () => {
  // Currently only supports sync operations and therefore requires inputs to be of type ArrayBuffer or a Uint8Array
  input.files?.[0]?
    .arrayBuffer()
    .then((buffer) => getRowsWithZodSchema(buffer, xlsxSchema, zodSchema))
    .then((rows) => {
      // Rows is a list of the objects that passed validation
    });
});

📦 Usage in Node

To use the Node version of this package, import it from the Node entry-point.

Getting all rows

import { getAllRows } from "xlsx-wasm-parser/node";
import fs from "fs";

const rows = getAllRows(fs.readFileSync("file.xlsx"));
// Rows is a 2d array of cells

Getting rows based on a schema

import { getParsedRows } from "xlsx-wasm-parser/node";
import fs from "fs";

const xlsxSchema = [
  [0, "name"],
  [1, "age"],
  [2, "address"],
] as [number, string][];
const rows = getParsedRows(fs.readFileSync("file.xlsx"), xlsxSchema);
// Rows is a list of objects based on the schema

To use the validation feature for Node, import the getParsedRowsWithZodSchema function from the node/validation entry-point.

With Zod Validation

import { getParsedRowsWithZodSchema } from "xlsx-wasm-parser/node/validation";
import fs from "fs";

const xlsxSchema = [
  [0, "name"],
  [1, "age"],
  [2, "address"],
] as [number, string][];

const zodSchema = z.object({
  name: z.string(),
  age: z.number(),
  address: z.string(),
});

const rows = getParsedRowsWithZodSchema(
  fs.readFileSync("file.xlsx"),
  xlsxSchema,
  zodSchema
);

// Rows is a list of the objects that passed validation

Benchmarks

Coming soon! I need to write fair implementations of the other libraries first. However from what I've been able to measure so far I can tell you it's fast.

Contributing

Currently there is a lot to do so all contributions are appreciated!

• Add support for more XLSX features, such as formatting, formulas, VBA, etc.
• Allow for async operations
• Allow for input of Blob, File, etc.
• Allow to pass an object of options to the parser for things like sheet name, etc.
• Add options for dates, currently all dates are assumed to be UTC and are returned as an ISO-8601 string
• Add CI/CD
• Add integration with more validation libraries
• Add benchmarks
• Allow users to pass in a list of objects instead of a list of tuples for the xlsx-schema