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Generate excel file from json data
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Aleksei Kolosov
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.gitignore init Feb 14, 2019
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JSON2Excel is a Rust and WebAssembly-based library that allows converting JSON files into Excel ones at ease.

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 json2excel-wasm
  • import the module
// worker.js
import "json2excel-wasm";
  • use the module in the app
// app.js
const worker = new Worker("worker.js");

function doConvert(){
        type: "convert",
        data: json_data_to_export

worker.addEventListener("message", e => {
    if ( === "ready"){
        const blob =;
        //excel file is ready to be downloaded!

        const a = document.createElement("a");
        a.href = URL.createObjectURL(blob); = "data.xlsx";

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);

Input format

interface IConvertMessageData {
    uid?: string;
    data: ISheetData;
    styles?: IStyles[];
    wasmPath?: string; // use cdn by default

interface IReadyMessageData {
    uid: string; // same as incoming uid
    blob: Blob;

interface ISheetData {
    name?: string;
    cols?: IColumnData[];
    rows?: IRowData[];
    cells?: IDataCell[][]; // if cells mising, use plain
    plain?: string[][];

    merged?: IMergedCells;

interface IMergedCells {
    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;
    align?: string;

    background?: string;
    color?: string;

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

    format?: string;



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