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How can I read .xlsx row using javascript and convert it to .json file

I have some trouble on on converting my code to .json file.
document.getElementById('button').addEventListener("click", () => {
XLSX.utils.json_to_sheet(data, 'out.xlsx');
if(selectedFile){
let fileReader = new FileReader();
fileReader.readAsBinaryString(selectedFile);
fileReader.onload = (event)=>{
let data = event.target.result;
let workbook = XLSX.read(data,{type:"binary"});
console.log(workbook);
workbook.SheetNames.forEach(sheet => {
let rowObject = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheet]);
console.log(rowObject);
document.getElementById("jsondata").innerHTML = JSON.stringify(rowObject,undefined,4)
});
}
}
});
Also I need to read xlsx file per row and convert it as a .json file
Thanks for the help!

Read Excel File and Store it in array using javascript [duplicate]

I am able to read Excel file via FileReader but it outputs text as well as weird characters with it. I need to read xls file row-wise, read data in every column and convert it to JSON.
How to read xls file row by row?

Below Function converts the Excel sheet (XLSX format) data to JSON. you can add promise to the function.
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
var ExcelToJSON = function() {
this.parseExcel = function(file) {
var reader = new FileReader();
reader.onload = function(e) {
var data = e.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function(sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
var json_object = JSON.stringify(XL_row_object);
console.log(json_object);
})
};
reader.onerror = function(ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
};
};
</script>
Below post has the code for XLS format Excel to JSON javascript code?

Old question, but I should note that the general task of parsing XLS files from javascript is tedious and difficult but not impossible.
I have basic parsers implemented in pure JS:
http://oss.sheetjs.com/js-xls/ (XLS files, what you wanted)
http://oss.sheetjs.com/js-xlsx/ (XLSX/XLSM/XLSB files)
Both pages are HTML5 File API-driven XLS/XLSX parsers (you can drag-drop your file and it will print out the data in the cells in a comma-separated list). You can also generate JSON objects (assuming the first row is a header row).
The test suite http://oss.sheetjs.com/ shows a version that uses XHR to get and parse files.

Upload an excel file here and you can get the data in JSON format in console:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
var ExcelToJSON = function() {
this.parseExcel = function(file) {
var reader = new FileReader();
reader.onload = function(e) {
var data = e.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function(sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
var json_object = JSON.stringify(XL_row_object);
console.log(JSON.parse(json_object));
jQuery('#xlx_json').val(json_object);
})
};
reader.onerror = function(ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
};
};
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object
var xl2json = new ExcelToJSON();
xl2json.parseExcel(files[0]);
}
</script>
<form enctype="multipart/form-data">
<input id="upload" type=file name="files[]">
</form>
<textarea class="form-control" rows=35 cols=120 id="xlx_json"></textarea>
<script>
document.getElementById('upload').addEventListener('change', handleFileSelect, false);
</script>
This is a combination of the following Stackoverflow posts:
https://stackoverflow.com/a/37083658/4742733
https://stackoverflow.com/a/39515846/4742733
Good Luck...

This code can help youMost of the time jszip.js is not working so include xlsx.full.min.js in your js code.
Html Code
<input type="file" id="file" ng-model="csvFile"
onchange="angular.element(this).scope().ExcelExport(event)"/>
Javascript
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js">
</script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js">
</script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.10.8/xlsx.full.min.js">
</script>
$scope.ExcelExport= function (event) {
var input = event.target;
var reader = new FileReader();
reader.onload = function(){
var fileData = reader.result;
var wb = XLSX.read(fileData, {type : 'binary'});
wb.SheetNames.forEach(function(sheetName){
var rowObj =XLSX.utils.sheet_to_row_object_array(wb.Sheets[sheetName]);
var jsonObj = JSON.stringify(rowObj);
console.log(jsonObj)
})
};
reader.readAsBinaryString(input.files[0]);
};

If you want the simplest and tiniest way of reading an *.xlsx file in a browser then this library might do:
https://catamphetamine.gitlab.io/read-excel-file/
<input type="file" id="input" />
import readXlsxFile from 'read-excel-file'
const input = document.getElementById('input')
input.addEventListener('change', () => {
readXlsxFile(input.files[0]).then((data) => {
// `data` is an array of rows
// each row being an array of cells.
})
})
In the example above data is raw string data.
It can be parsed to JSON with a strict schema by passing schema argument. See API docs for an example of that.
API docs:
http://npmjs.com/package/read-excel-file

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
var ExcelToJSON = function() {
this.parseExcel = function(file) {
var reader = new FileReader();
reader.onload = function(e) {
var data = e.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function(sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
var json_object = JSON.stringify(XL_row_object);
console.log(JSON.parse(json_object));
jQuery( '#xlx_json' ).val( json_object );
})
};
reader.onerror = function(ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
};
};
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object
var xl2json = new ExcelToJSON();
xl2json.parseExcel(files[0]);
}
</script>
<form enctype="multipart/form-data">
<input id="upload" type=file name="files[]">
</form>
<textarea class="form-control" rows=35 cols=120 id="xlx_json"></textarea>
<script>
document.getElementById('upload').addEventListener('change', handleFileSelect, false);
</script>

Thank you for the answer above, I think the scope (of answers) is completed but I would like to add a "react way" for whoever using react.
Create a file called importData.js:
import React, {Component} from 'react';
import XLSX from 'xlsx';
export default class ImportData extends Component{
constructor(props){
super(props);
this.state={
excelData:{}
}
}
excelToJson(reader){
var fileData = reader.result;
var wb = XLSX.read(fileData, {type : 'binary'});
var data = {};
wb.SheetNames.forEach(function(sheetName){
var rowObj =XLSX.utils.sheet_to_row_object_array(wb.Sheets[sheetName]);
var rowString = JSON.stringify(rowObj);
data[sheetName] = rowString;
});
this.setState({excelData: data});
}
loadFileXLSX(event){
var input = event.target;
var reader = new FileReader();
reader.onload = this.excelToJson.bind(this,reader);
reader.readAsBinaryString(input.files[0]);
}
render(){
return (
<input type="file" onChange={this.loadFileXLSX.bind(this)}/>
);
}
}
Then you can use the component in the render method like:
import ImportData from './importData.js';
import React, {Component} from 'react';
class ParentComponent extends Component{
render(){
return (<ImportData/>);
}
}
<ImportData/> would set the data to its own state, you can access Excel data in the "parent component" by following this:

readExcelFile = async ( file ) =>
{
const fileReader = new FileReader();
fileReader.readAsArrayBuffer( file );
fileReader.onload = ( e ) =>
{
const bufferArray = e.target.result;
const wb = XLSX.read( bufferArray, { type: "buffer" } );
const wsname = wb.SheetNames[ 0 ];
const ws = wb.Sheets[ wsname ];
const data = XLSX.utils.sheet_to_json( ws );
console.log(data);
};
};
<input type="file" name="excelfile" id="excelfile" readExcelFile(file)>

Simplest way to do it using CDN with plain javascript
<script src="https://unpkg.com/read-excel-file#5.x/bundle/read-excel-file.min.js"></script>
<html>
<h1>read-excel-file</h1>
</html>
<script>
var input = document.createElement("INPUT");
input.setAttribute("type", "file");
document.body.appendChild(input)
input.addEventListener('change', function() {
readXlsxFile(input.files[0]).then(function(rows) {
console.log(rows)
})
})
</script>
Simplest way to it using plain javascript.

If you are ever wondering how to read a file from server this code might be helpful.
Restrictions :
File should be in the server (Local/Remote).
You will have to setup headers or have CORS google plugin.
<Head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script lang="javascript" src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.12.4/xlsx.core.min.js"></script>
</head>
<body>
<script>
/* set up XMLHttpRequest */
// replace it with your file path in local server
var url = "http://localhost/test.xlsx";
var oReq = new XMLHttpRequest();
oReq.open("GET", url, true);
oReq.responseType = "arraybuffer";
oReq.onload = function(e) {
var arraybuffer = oReq.response;
/* convert data to binary string */
var data = new Uint8Array(arraybuffer);
var arr = new Array();
for (var i = 0; i != data.length; ++i) {
arr[i] = String.fromCharCode(data[i]);
}
var bstr = arr.join("");
var cfb = XLSX.read(bstr, { type: 'binary' });
cfb.SheetNames.forEach(function(sheetName, index) {
// Obtain The Current Row As CSV
var fieldsObjs = XLS.utils.sheet_to_json(cfb.Sheets[sheetName]);
fieldsObjs.map(function(field) {
$("#my_file_output").append('<input type="checkbox" value="' + field.Fields + '">' + field.Fields + '<br>');
});
});
}
oReq.send();
</script>
</body>
<div id="my_file_output">
</div>
</html>

include the xslx.js , xlsx.full.min.js , jszip.js
add a onchange event handler to the file input
function showDataExcel(event)
{
var file = event.target.files[0];
var reader = new FileReader();
var excelData = [];
reader.onload = function (event) {
var data = event.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function (sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
for (var i = 0; i < XL_row_object.length; i++)
{
excelData.push(XL_row_object[i]["your column name"]);
}
var json_object = JSON.stringify(XL_row_object);
console.log(json_object);
alert(excelData);
})
};
reader.onerror = function (ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
}

This is for react js
import React, { useState } from "react";
import logo from "./logo.svg";
import "./App.css";
import * as XLSX from "xlsx";
function App() {
const [items, setItems] = useState([]);
const readExcel = (file) => {
const promise = new Promise((resolve, reject) => {
const fileReader = new FileReader();
fileReader.readAsArrayBuffer(file);
fileReader.onload = (e) => {
const bufferArray = e.target.result;
const wb = XLSX.read(bufferArray, { type: "buffer" });
const wsname = wb.SheetNames[0];
const ws = wb.Sheets[wsname];
const data = XLSX.utils.sheet_to_json(ws);
resolve(data);
};
fileReader.onerror = (error) => {
reject(error);
};
});
promise.then((d) => {
setItems(d);
});
};
return (
<div>
<input
type="file"
onChange={(e) => {
const file = e.target.files[0];
readExcel(file);
}}
/>
<table class="table container">
<thead>
<tr>
<th scope="col">Item</th>
<th scope="col">Description</th>
</tr>
</thead>
<tbody>
{items.map((d) => (
<tr key={d.Item}>
<th>{d.Item}</th>
<td>{d.Description}</td>
</tr>
))}
</tbody>
</table>
</div>
);
}
export default App;

Below code will work in reading XLSX file using Javascript
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.7.7/xlsx.core.min.js"></script>
<script>
function handleFile(e)
{
//Get the files from Upload control
var files = e.target.files;
var i, f;
var title;
var choice;
//Loop through files
for (i = 0, f = files[i]; i != files.length; ++i)
{
var reader = new FileReader();
var name = f.name;
reader.onload = function(e)
{
debugger;
var data = e.target.result;
var result;
var workbook = XLSX.read(data,
{
type: 'binary'
});
var sheet_name_list = workbook.SheetNames;
var roa;
sheet_name_list.forEach(function(y)
{
/* iterate through sheets */
//Convert the cell value to Json
roa = XLSX.utils.sheet_to_json(workbook.Sheets[y]);
if (roa.length > 0)
{
result = roa;
}
});
};
reader.readAsArrayBuffer(f);
}
}
$(document).ready(function()
{
$('#files').change(handleFile);
});
</script>
<input type="file" id="files" name="files"/>

The weird characters you got from reading the Excel file from the FileReader API comes from the structure of the file that differs a lot from a text file.
So reading it as text with the FileReader API will give those weirds character as a result.
What you can do is to use the FileReader API to read it as a binary string.
At this point if you try to log that binary string you will also get weirds characters.
In order to get your file content you need to parse that binary string to extract the data it contains. This can be done quite easily using SheetJS.
import { read, writeFileXLSX, utils } from "https://cdn.sheetjs.com/xlsx-0.18.7/package/xlsx.mjs";
const workbook = read(data, {
type:'binary',
});
data is the binary string resulting from reading an Excel file as a binary string with the FileReader API.
workbook is an object that contains all the data of your file.
The workbook.Sheets instruction will give you access to all the sheets that are in the file.
workbook.Sheets.sheet1 will give you access to the content of the first sheet of the file.
All the related arrays are from the {key:value} type.
The content of a sheet accessed this way is a single dimension object array wich contains all the cells of the sheet starting from the first cell of the header to the last cell wich contains data. Each of those cells has a key like this 'A1', 'B250', 'J3'
This array also have two more entries with those keys '!margin' and '!ref':
'!margin' refers to cells margins so it may not represent any interest.
'!ref' is more interesting as it contains the plage of cells containing data wich is a string like this 'A1:J215' from it you could get the amount of lines or the char of the last column.
If you want more informations you could check the SheetJS documentation and there is a more detailed example here : How to read an excel file contents on client side?
Note :
If you want to use this import statement in an html page you'll need to do it inside those scripts tags : <script type="module" defer> ... </script>
Here is a codepen where you can test this method. There's only the most basic method. There are some shorter ways to do the same by using the SheetJS utils functions to convert directly the sheet content to another format.

XLS is a binary proprietary format used by Microsoft. Parsing XLS with server side languages is very difficult without using some specific library or Office Interop. Doing this with javascript is mission impossible. Thanks to the HTML5 File API you can read its binary contents but in order to parse and interpret it you will need to dive into the specifications of the XLS format. Starting from Office 2007, Microsoft embraced the Open XML file formats (xslx for Excel) which is a standard.

var excel=new ActiveXObject("Excel.Application");
var book=excel.Workbooks.Open(your_full_file_name_here.xls);
var sheet=book.Sheets.Item(1);
var value=sheet.Range("A1");
when you have the sheet. You could use VBA functions as you do in Excel.

How can i get the data From FileReader() onload

I am converting excel data to json using XLSX and have to send the received data from onload to other functions. The conversion of excel to json is working just file.
var files = e.target.files;
var f = files[0];
var reader = new FileReader();
reader.onload = e => {
var data = new Uint8Array(e.target.result);
var workbook = XLSX.read(data, { type: "array" });
let sheetName = workbook.SheetNames[0];
console.log(workbook);
let worksheet = workbook.Sheets[sheetName];
console.log("insde", XLSX.utils.sheet_to_json(worksheet));
console.log(XLSX.utils.sheet_to_json(worksheet))
};
reader.readAsArrayBuffer(f);
i just want to send XLSX.utils.sheet_to_json(worksheet) as data in other function
Thank your for your help :) .

You'd either pass back a callback or make this a Promisified function.
const fileToSheet = (file, callback) =>
var reader = new FileReader();
reader.onload = e => {
const data = new Uint8Array(e.target.result);
const workbook = XLSX.read(data, { type: "array" });
const sheetName = workbook.SheetNames[0];
const worksheet = workbook.Sheets[sheetName];
callback(XLSX.utils.sheet_to_json(worksheet));
}
reader.readAsArrayBuffer(file);
}
// elsewhere in your program
const files = e.target.files;
const f = files[0];
fileToSheet(file, console.log);
You can easily promisify this, and add error handling in the standard callback format that people usually use for a callback.

Reading local Excel file with js-xlsx using Angular 13?

I have my Angular-CLI frontend development server running locally on localhost:4200
I need to get a local Excel file stored on my PC, read its content and
make some calls to an API from the client side.
I'm trying to use js-xlsx, got it installed with npm install xlsx but I can't find how to get the file and read its content.
How can I import a local excel file with js-xlsx in Angular 13?

Here is working Example
onFileChange(ev) {
let workBook = null;
let jsonData = null;
const reader = new FileReader();
const file = ev.target.files[0];
reader.onload = (event) => {
const data = reader.result;
workBook = XLSX.read(data, { type: 'binary' });
jsonData = workBook.SheetNames.reduce((initial, name) => {
const sheet = workBook.Sheets[name];
initial[name] = XLSX.utils.sheet_to_json(sheet);
return initial;
}, {});
const dataString = JSON.stringify(jsonData);
document.getElementById('output').innerHTML = dataString.slice(0, 300).concat("...");
this.setDownload(dataString);
}
reader.readAsBinaryString(file);
}

In my case i want data like
[['1','2'],['3','4']]
also data like
{'1':'3', '2':'4'}
So that i did following code
uploadFile(uploadedFile){
let workBook = null;
const reader = new FileReader();
const file = uploadedFile[0];
reader.onload = (event) => {
const data = reader.result;
workBook = XLSX.read(data, { type: 'binary' });
const sheet_name_list = workBook.SheetNames;
this.xlData = XLSX.utils.sheet_to_json(workBook.Sheets[sheet_name_list[0]]);
log("xlData >>> ",JSON.stringify(this.xlData));
this.arraySaparater = (XLSX.utils.sheet_to_json(workBook.Sheets[sheet_name_list[0]], { header: 1 }));
this.arraySaparater = this.arraySaparater.filter((row)=>{
if(Array.isArray(row) && row.length){
return row;
}
else{
return false;
}
});
log('ArraySaparater >>>',JSON.stringify(this.arraySaparater));
}
reader.readAsBinaryString(file);
}

How to parse Excel (XLS) file in Javascript/HTML5

I am able to read Excel file via FileReader but it outputs text as well as weird characters with it. I need to read xls file row-wise, read data in every column and convert it to JSON.
How to read xls file row by row?

Below Function converts the Excel sheet (XLSX format) data to JSON. you can add promise to the function.
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
var ExcelToJSON = function() {
this.parseExcel = function(file) {
var reader = new FileReader();
reader.onload = function(e) {
var data = e.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function(sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
var json_object = JSON.stringify(XL_row_object);
console.log(json_object);
})
};
reader.onerror = function(ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
};
};
</script>
Below post has the code for XLS format Excel to JSON javascript code?

Old question, but I should note that the general task of parsing XLS files from javascript is tedious and difficult but not impossible.
I have basic parsers implemented in pure JS:
http://oss.sheetjs.com/js-xls/ (XLS files, what you wanted)
http://oss.sheetjs.com/js-xlsx/ (XLSX/XLSM/XLSB files)
Both pages are HTML5 File API-driven XLS/XLSX parsers (you can drag-drop your file and it will print out the data in the cells in a comma-separated list). You can also generate JSON objects (assuming the first row is a header row).
The test suite http://oss.sheetjs.com/ shows a version that uses XHR to get and parse files.

Upload an excel file here and you can get the data in JSON format in console:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
var ExcelToJSON = function() {
this.parseExcel = function(file) {
var reader = new FileReader();
reader.onload = function(e) {
var data = e.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function(sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
var json_object = JSON.stringify(XL_row_object);
console.log(JSON.parse(json_object));
jQuery('#xlx_json').val(json_object);
})
};
reader.onerror = function(ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
};
};
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object
var xl2json = new ExcelToJSON();
xl2json.parseExcel(files[0]);
}
</script>
<form enctype="multipart/form-data">
<input id="upload" type=file name="files[]">
</form>
<textarea class="form-control" rows=35 cols=120 id="xlx_json"></textarea>
<script>
document.getElementById('upload').addEventListener('change', handleFileSelect, false);
</script>
This is a combination of the following Stackoverflow posts:
https://stackoverflow.com/a/37083658/4742733
https://stackoverflow.com/a/39515846/4742733
Good Luck...

This code can help youMost of the time jszip.js is not working so include xlsx.full.min.js in your js code.
Html Code
<input type="file" id="file" ng-model="csvFile"
onchange="angular.element(this).scope().ExcelExport(event)"/>
Javascript
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js">
</script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js">
</script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.10.8/xlsx.full.min.js">
</script>
$scope.ExcelExport= function (event) {
var input = event.target;
var reader = new FileReader();
reader.onload = function(){
var fileData = reader.result;
var wb = XLSX.read(fileData, {type : 'binary'});
wb.SheetNames.forEach(function(sheetName){
var rowObj =XLSX.utils.sheet_to_row_object_array(wb.Sheets[sheetName]);
var jsonObj = JSON.stringify(rowObj);
console.log(jsonObj)
})
};
reader.readAsBinaryString(input.files[0]);
};

If you want the simplest and tiniest way of reading an *.xlsx file in a browser then this library might do:
https://catamphetamine.gitlab.io/read-excel-file/
<input type="file" id="input" />
import readXlsxFile from 'read-excel-file'
const input = document.getElementById('input')
input.addEventListener('change', () => {
readXlsxFile(input.files[0]).then((data) => {
// `data` is an array of rows
// each row being an array of cells.
})
})
In the example above data is raw string data.
It can be parsed to JSON with a strict schema by passing schema argument. See API docs for an example of that.
API docs:
http://npmjs.com/package/read-excel-file

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
var ExcelToJSON = function() {
this.parseExcel = function(file) {
var reader = new FileReader();
reader.onload = function(e) {
var data = e.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function(sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
var json_object = JSON.stringify(XL_row_object);
console.log(JSON.parse(json_object));
jQuery( '#xlx_json' ).val( json_object );
})
};
reader.onerror = function(ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
};
};
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object
var xl2json = new ExcelToJSON();
xl2json.parseExcel(files[0]);
}
</script>
<form enctype="multipart/form-data">
<input id="upload" type=file name="files[]">
</form>
<textarea class="form-control" rows=35 cols=120 id="xlx_json"></textarea>
<script>
document.getElementById('upload').addEventListener('change', handleFileSelect, false);
</script>

Thank you for the answer above, I think the scope (of answers) is completed but I would like to add a "react way" for whoever using react.
Create a file called importData.js:
import React, {Component} from 'react';
import XLSX from 'xlsx';
export default class ImportData extends Component{
constructor(props){
super(props);
this.state={
excelData:{}
}
}
excelToJson(reader){
var fileData = reader.result;
var wb = XLSX.read(fileData, {type : 'binary'});
var data = {};
wb.SheetNames.forEach(function(sheetName){
var rowObj =XLSX.utils.sheet_to_row_object_array(wb.Sheets[sheetName]);
var rowString = JSON.stringify(rowObj);
data[sheetName] = rowString;
});
this.setState({excelData: data});
}
loadFileXLSX(event){
var input = event.target;
var reader = new FileReader();
reader.onload = this.excelToJson.bind(this,reader);
reader.readAsBinaryString(input.files[0]);
}
render(){
return (
<input type="file" onChange={this.loadFileXLSX.bind(this)}/>
);
}
}
Then you can use the component in the render method like:
import ImportData from './importData.js';
import React, {Component} from 'react';
class ParentComponent extends Component{
render(){
return (<ImportData/>);
}
}
<ImportData/> would set the data to its own state, you can access Excel data in the "parent component" by following this:

readExcelFile = async ( file ) =>
{
const fileReader = new FileReader();
fileReader.readAsArrayBuffer( file );
fileReader.onload = ( e ) =>
{
const bufferArray = e.target.result;
const wb = XLSX.read( bufferArray, { type: "buffer" } );
const wsname = wb.SheetNames[ 0 ];
const ws = wb.Sheets[ wsname ];
const data = XLSX.utils.sheet_to_json( ws );
console.log(data);
};
};
<input type="file" name="excelfile" id="excelfile" readExcelFile(file)>

Simplest way to do it using CDN with plain javascript
<script src="https://unpkg.com/read-excel-file#5.x/bundle/read-excel-file.min.js"></script>
<html>
<h1>read-excel-file</h1>
</html>
<script>
var input = document.createElement("INPUT");
input.setAttribute("type", "file");
document.body.appendChild(input)
input.addEventListener('change', function() {
readXlsxFile(input.files[0]).then(function(rows) {
console.log(rows)
})
})
</script>
Simplest way to it using plain javascript.

If you are ever wondering how to read a file from server this code might be helpful.
Restrictions :
File should be in the server (Local/Remote).
You will have to setup headers or have CORS google plugin.
<Head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script lang="javascript" src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.12.4/xlsx.core.min.js"></script>
</head>
<body>
<script>
/* set up XMLHttpRequest */
// replace it with your file path in local server
var url = "http://localhost/test.xlsx";
var oReq = new XMLHttpRequest();
oReq.open("GET", url, true);
oReq.responseType = "arraybuffer";
oReq.onload = function(e) {
var arraybuffer = oReq.response;
/* convert data to binary string */
var data = new Uint8Array(arraybuffer);
var arr = new Array();
for (var i = 0; i != data.length; ++i) {
arr[i] = String.fromCharCode(data[i]);
}
var bstr = arr.join("");
var cfb = XLSX.read(bstr, { type: 'binary' });
cfb.SheetNames.forEach(function(sheetName, index) {
// Obtain The Current Row As CSV
var fieldsObjs = XLS.utils.sheet_to_json(cfb.Sheets[sheetName]);
fieldsObjs.map(function(field) {
$("#my_file_output").append('<input type="checkbox" value="' + field.Fields + '">' + field.Fields + '<br>');
});
});
}
oReq.send();
</script>
</body>
<div id="my_file_output">
</div>
</html>

include the xslx.js , xlsx.full.min.js , jszip.js
add a onchange event handler to the file input
function showDataExcel(event)
{
var file = event.target.files[0];
var reader = new FileReader();
var excelData = [];
reader.onload = function (event) {
var data = event.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function (sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
for (var i = 0; i < XL_row_object.length; i++)
{
excelData.push(XL_row_object[i]["your column name"]);
}
var json_object = JSON.stringify(XL_row_object);
console.log(json_object);
alert(excelData);
})
};
reader.onerror = function (ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
}

This is for react js
import React, { useState } from "react";
import logo from "./logo.svg";
import "./App.css";
import * as XLSX from "xlsx";
function App() {
const [items, setItems] = useState([]);
const readExcel = (file) => {
const promise = new Promise((resolve, reject) => {
const fileReader = new FileReader();
fileReader.readAsArrayBuffer(file);
fileReader.onload = (e) => {
const bufferArray = e.target.result;
const wb = XLSX.read(bufferArray, { type: "buffer" });
const wsname = wb.SheetNames[0];
const ws = wb.Sheets[wsname];
const data = XLSX.utils.sheet_to_json(ws);
resolve(data);
};
fileReader.onerror = (error) => {
reject(error);
};
});
promise.then((d) => {
setItems(d);
});
};
return (
<div>
<input
type="file"
onChange={(e) => {
const file = e.target.files[0];
readExcel(file);
}}
/>
<table class="table container">
<thead>
<tr>
<th scope="col">Item</th>
<th scope="col">Description</th>
</tr>
</thead>
<tbody>
{items.map((d) => (
<tr key={d.Item}>
<th>{d.Item}</th>
<td>{d.Description}</td>
</tr>
))}
</tbody>
</table>
</div>
);
}
export default App;

Below code will work in reading XLSX file using Javascript
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.7.7/xlsx.core.min.js"></script>
<script>
function handleFile(e)
{
//Get the files from Upload control
var files = e.target.files;
var i, f;
var title;
var choice;
//Loop through files
for (i = 0, f = files[i]; i != files.length; ++i)
{
var reader = new FileReader();
var name = f.name;
reader.onload = function(e)
{
debugger;
var data = e.target.result;
var result;
var workbook = XLSX.read(data,
{
type: 'binary'
});
var sheet_name_list = workbook.SheetNames;
var roa;
sheet_name_list.forEach(function(y)
{
/* iterate through sheets */
//Convert the cell value to Json
roa = XLSX.utils.sheet_to_json(workbook.Sheets[y]);
if (roa.length > 0)
{
result = roa;
}
});
};
reader.readAsArrayBuffer(f);
}
}
$(document).ready(function()
{
$('#files').change(handleFile);
});
</script>
<input type="file" id="files" name="files"/>

The weird characters you got from reading the Excel file from the FileReader API comes from the structure of the file that differs a lot from a text file.
So reading it as text with the FileReader API will give those weirds character as a result.
What you can do is to use the FileReader API to read it as a binary string.
At this point if you try to log that binary string you will also get weirds characters.
In order to get your file content you need to parse that binary string to extract the data it contains. This can be done quite easily using SheetJS.
import { read, writeFileXLSX, utils } from "https://cdn.sheetjs.com/xlsx-0.18.7/package/xlsx.mjs";
const workbook = read(data, {
type:'binary',
});
data is the binary string resulting from reading an Excel file as a binary string with the FileReader API.
workbook is an object that contains all the data of your file.
The workbook.Sheets instruction will give you access to all the sheets that are in the file.
workbook.Sheets.sheet1 will give you access to the content of the first sheet of the file.
All the related arrays are from the {key:value} type.
The content of a sheet accessed this way is a single dimension object array wich contains all the cells of the sheet starting from the first cell of the header to the last cell wich contains data. Each of those cells has a key like this 'A1', 'B250', 'J3'
This array also have two more entries with those keys '!margin' and '!ref':
'!margin' refers to cells margins so it may not represent any interest.
'!ref' is more interesting as it contains the plage of cells containing data wich is a string like this 'A1:J215' from it you could get the amount of lines or the char of the last column.
If you want more informations you could check the SheetJS documentation and there is a more detailed example here : How to read an excel file contents on client side?
Note :
If you want to use this import statement in an html page you'll need to do it inside those scripts tags : <script type="module" defer> ... </script>
Here is a codepen where you can test this method. There's only the most basic method. There are some shorter ways to do the same by using the SheetJS utils functions to convert directly the sheet content to another format.

XLS is a binary proprietary format used by Microsoft. Parsing XLS with server side languages is very difficult without using some specific library or Office Interop. Doing this with javascript is mission impossible. Thanks to the HTML5 File API you can read its binary contents but in order to parse and interpret it you will need to dive into the specifications of the XLS format. Starting from Office 2007, Microsoft embraced the Open XML file formats (xslx for Excel) which is a standard.

var excel=new ActiveXObject("Excel.Application");
var book=excel.Workbooks.Open(your_full_file_name_here.xls);
var sheet=book.Sheets.Item(1);
var value=sheet.Range("A1");
when you have the sheet. You could use VBA functions as you do in Excel.