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Convert excel file to json data
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Excel2json is a Rust and WebAssembly-based library that allows easily converting files in Excel format to JSON files.

npm version

How to build

yarn install
// build js code
yarn build
// rebuild wasm code
// rust toolchain is required
yarn build-wasm

How to use via npm

  • install the module
yarn add excel2json-wasm
  • import the module
// worker.js
  • use the module in the app
// app.js
const worker = new Worker("worker.js");

// convert excel file to json
    type: "convert",
    data: file_object_or_typed_array

worker.addEventListener("message", e => {
    if ( === "ready"){
        const data =;
        const styles =;

        //json data is ready
        console.log(data, styles)

How to use from CDN

CDN links are the following:

In case you use build system like webpack, it is advised to wrap the link to CDN source into a blob object to avoid possible breakdowns:

var url = window.URL.createObjectURL(new Blob([
], { type: "text/javascript" }));

var worker = new Worker(url);

Output format

interface IConvertMessageData {
    uid?: string;
    data: Uint8Array | File;
    sheet?: string;
    styles?: boolean;
    wasmPath?: string;

interface IReadyMessageData {
    uid: string;
    data: ISheetData[];
    styles: IStyles[];

interface ISheetData {
    name: string;
    cols: IColumnData[];
    rows: IRowData[];
    cells: IDataCell[][];   // null for empty cell

    merged: IMergedCell[];

interface IMergedCell {
    from: IDataPoint;
    to: IDataPoint;

interface IDataPoint {
    column: number; 
    row: number;

interface IColumnData {
    width: number;

interface IRowData {
    height: number;

interface IDataCell{
    v: string;
    s: number:

interface IStyle {
    fontSize?: string;
    fontFamily?: string;

    background?: string;
    color?: string;

    fontWeight?: string;
    fontStyle?: string;
    textDecoration?: string;

    textAlign?: string;
    verticalAlign?: string;

    borderLeft?: string;
    borderTop?: string;
    borderBottom?: string;
    borderRight?: string;

    format?: string;



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