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javascript – Reading local Excel file with js-xlsx using Angular 9?

Posted by: admin April 23, 2020 Leave a comment

Questions:

I have my Angular-CLI frontend development server running locally on localhost:4200

For specific reasons I need to get a local Excel file stored on my PC, read its content and make some calls to an API. And it must be 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 9?

Note: If it is possible/easier using pure JavaScript it is also valid for me.

How to&Answers:

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);
  }

Answer:

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);
}