Angular 4: How to read data from Excel?

Question

I am not able to get data from an Excel sheet in Angular 4. Below is my code sample.

HTML code:

<input id="my-file-selector" type="file" (change)="uploadData($event)" name="uploadExcel">

upload.component.ts:

public uploadData(event: any) : void { 
    // get data from file upload       
    let filesData = event.target.files;
    console.log(filesData[0]);
}

Answer 1

You should follow these 3 steps

step 1: import ts-xlsx refer: https://www.npmjs.com/package/ts-xlsx for installation

step 2: Using FileReader convert to arraybuffer

step 3: Reading the arraybuffer with XLSX and converting as workbook

HTML CODE

<input type="file" style="display: inline-block;" (change)="incomingfile($event)" placeholder="Upload file" accept=".xlsx">
<button type="button" class="btn btn-info" (click)="Upload()" >Upload</button>

Typescript

//import it

    import * as XLSX from 'ts-xlsx';

//inside export class

arrayBuffer:any;
file:File;
incomingfile(event) 
  {
  this.file= event.target.files[0]; 
  }

 Upload() {
      let fileReader = new FileReader();
        fileReader.onload = (e) => {
            this.arrayBuffer = fileReader.result;
            var data = new Uint8Array(this.arrayBuffer);
            var arr = new Array();
            for(var i = 0; i != data.length; ++i) arr[i] = String.fromCharCode(data[i]);
            var bstr = arr.join("");
            var workbook = XLSX.read(bstr, {type:"binary"});
            var first_sheet_name = workbook.SheetNames[0];
            var worksheet = workbook.Sheets[first_sheet_name];
            console.log(XLSX.utils.sheet_to_json(worksheet,{raw:true}));
        }
        fileReader.readAsArrayBuffer(this.file);
}

Answer 2

You can use SheetJs/xlsx package from npm to get the data from excel as a json object in Angular / Ionic.

Just follow these steps:

1) npm install --save xlsx

2) Now in your component file import xlsx

import * as XLSX from 'xlsx';

3) Now attach this function in the change event of input tag of type file

onFileChange(event: any) {
    /* wire up file reader */
    const target: DataTransfer = <DataTransfer>(event.target);
    if (target.files.length !== 1) {
      throw new Error('Cannot use multiple files');
    }
    const reader: FileReader = new FileReader();
    reader.readAsBinaryString(target.files[0]);
    reader.onload = (e: any) => {
      /* create workbook */
      const binarystr: string = e.target.result;
      const wb: XLSX.WorkBook = XLSX.read(binarystr, { type: 'binary' });

      /* selected the first sheet */
      const wsname: string = wb.SheetNames[0];
      const ws: XLSX.WorkSheet = wb.Sheets[wsname];

      /* save data */
      const data = XLSX.utils.sheet_to_json(ws); // to get 2d array pass 2nd parameter as object {header: 1}
      console.log(data); // Data will be logged in array format containing objects
    };
 }

You can also refer to these utils method present in xlsx to perform different operation according to your need.

https://github.com/SheetJS/sheetjs#utility-functions

And also during read operation you can pass these parsing options inside object

https://github.com/SheetJS/sheetjs#parsing-options

For any other information refer to the doc

https://github.com/SheetJS/sheetjs

Hope this will help you or somebody else.

Answer 3

This package has been deprecated: https://www.npmjs.com/package/ts-xlsx

Use https://github.com/SheetJS/js-xlsx/.

And TypeScript or Angular 5: https://github.com/SheetJS/js-xlsx/tree/master/demos/typescript.

With import * as XLSX from 'xlsx';

Then use the steps in the answer, and it works perfectly.

Answer 4

I've tried the file upload and below is my steps and result with both data and header,

This will also support multiple sheet within the excel sheet,

1.npm install --save xlsx
    
2.import * as XLSX from 'xlsx';

3.HTML Code:

<input type="file" (change)="onFileChange($event)">

4.Angular Typescript:

  exceltoJson = {};

  onFileChange(event: any) {
    this.exceltoJson = {};
    let headerJson = {};
    /* wire up file reader */
    const target: DataTransfer = <DataTransfer>(event.target);
    // if (target.files.length !== 1) {
    //   throw new Error('Cannot use multiple files');
    // }
    const reader: FileReader = new FileReader();
    reader.readAsBinaryString(target.files[0]);
    console.log("filename", target.files[0].name);
    this.exceltoJson['filename'] = target.files[0].name;
    reader.onload = (e: any) => {
      /* create workbook */
      const binarystr: string = e.target.result;
      const wb: XLSX.WorkBook = XLSX.read(binarystr, { type: 'binary' });
      for (var i = 0; i < wb.SheetNames.length; ++i) {
        const wsname: string = wb.SheetNames[i];
        const ws: XLSX.WorkSheet = wb.Sheets[wsname];
        const data = XLSX.utils.sheet_to_json(ws); // to get 2d array pass 2nd parameter as object {header: 1}
        this.exceltoJson[`sheet${i + 1}`] = data;
        const headers = this.get_header_row(ws);
        headerJson[`header${i + 1}`] = headers;
        //  console.log("json",headers)
      }
      this.exceltoJson['headers'] = headerJson;
      console.log(this.exceltoJson);
    };
  }

  get_header_row(sheet) {
    var headers = [];
    var range = XLSX.utils.decode_range(sheet['!ref']);
    var C, R = range.s.r; /* start in the first row */
    /* walk every column in the range */
    for (C = range.s.c; C <= range.e.c; ++C) {
      var cell = sheet[XLSX.utils.encode_cell({ c: C, r: R })] /* find the cell in the first row */
      // console.log("cell",cell)
      var hdr = "UNKNOWN " + C; // <-- replace with your desired default 
      if (cell && cell.t) {
        hdr = XLSX.utils.format_cell(cell);
        headers.push(hdr);
      }
    }
    return headers;
  }

5.Result
{filename: "uploadedexcel.xlsx", sheet1: Array(212), sheet2: Array(8), headers: {…}}

Results holds the uploaded excel name, data in the sheet1 and sheet2 and also header in the sheet1 and sheet2.

The uploaded excel sheets has sheet1 and sheet2.