离子 |类型错误 | fs.createWriteStream 不是函数

Question

我正在尝试创建一个示例 excel 文件，但我收到错误“fs.createWriteStream 不是函数”。 下面是创建文件的代码-

import { Component } from '@angular/core';
import { NavController, Platform } from 'ionic-angular';
import * as Excel from "exceljs/dist/exceljs.js";

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

  constructor(platform: Platform) {
    platform.ready().then(() => {
      this.createSheetUsingExcelJs();
    });
  }

  ionViewDidLoad() {
  }

  createSheetUsingExcelJs() {
    let workbook = new Excel.Workbook();
    var worksheet = workbook.addWorksheet('My Sheet');

    worksheet.columns = [
      { header: 'Id', key: 'id', width: 10 },
      { header: 'Name', key: 'name', width: 32 },
      { header: 'D.O.B.', key: 'DOB', width: 10 }
    ];
    worksheet.addRow({ id: 1, name: 'Ionic Android', dob: new Date(1970, 1, 1) });
    worksheet.addRow({ id: 2, name: 'Ionic iOS', dob: new Date(1965, 1, 7) });
    var tempFilePath = 'C:/Users/mahmad/Downloads/temp.xlsx';
    console.log(workbook);

    workbook.xlsx.writeFile('temp.xlsx').then(function () {
      console.log('file is written');
    });
  }
}

请提出解决此问题的解决方案

Answer 1

从“exceljs/dist/exceljs.js”导入*为Excel；

要从 javascript 文件导入 typescript，需要使用库的类型定义文件。

在npm 中可用。

做：

npm i @types/exceljs --save-dev

为了导入：

import * as Excel from 'exceljs';

您可以在“DefinitelyTyped”repo的测试文件中查看样本

Answer 2

最后，使用ts-xlsx library 完成任务。 以下是我的代码-

import { Component, Injectable } from '@angular/core';
import { NavController, Platform } from 'ionic-angular';
import * as XLSX from 'ts-xlsx';
import { File } from '@ionic-native/file';
import { EmailComposer } from '@ionic-native/email-composer';

declare var cordova: any;
declare var window;

@Component({
  selector: 'page-home',
  templateUrl: 'home.html',
  providers: [File]
})

@Injectable()
export class HomePage {

  sheetNames: string[] = []
  sheets: any;

  constructor(public emailComposer: EmailComposer, platform: Platform, public file: File) {
    var objects = [["Header 1", "Header 2", "Header 3"], ["Value 1 1", "Value 1 2", "Value 1 3"], ["Value 2 1", "Value 2 2", "Value 2 3"]];

    platform.ready().then(() => {
      console.log(cordova.file.externalCacheDirectory + "report.xlsx");
      this.createXSLX(objects);
      this.sendEmail(cordova.file.externalCacheDirectory + "report.xlsx");
    });
  }

  createXSLX(data: any) {

    var pathFile = "";
    var fileName = "report.xlsx";
    let ws_name = "OrderDetails";

    let wb: XLSX.IWorkBook = {
      SheetNames: [],
      Sheets: {},
      Props: {}

    };
    let ws = this.sheet_from_array_of_arrays(data, {});

    /* add worksheet to workbook */
    wb.SheetNames.push(ws_name);
    wb.Sheets[ws_name] = ws;
    let wbout = XLSX.write(wb, { bookType: 'xlsx', type: 'binary' });

    let xslxBlob = new Blob([this.s2ab(wbout)], { type: "application/octet-stream" });
    pathFile = cordova.file.externalCacheDirectory;
    this.file.writeFile(pathFile, fileName, xslxBlob);
  }    

  sendEmail(data) {    
    this.emailComposer.isAvailable().then((available: boolean) => {
      if (available) {
        //Now we know we can send
      }
    });

    let email = {
      to: '',
      attachments: [data],
      subject: 'XLSX File',
      body: 'How are you? Nice greetings from Leipzig',
      isHtml: true
    };

    // Send a text message using default options
    this.emailComposer.open(email);
  }


  datenum(v, date1904): any {
    if (date1904) v += 1462;
    let epoch: any = Date.parse(v);
    return (epoch - new Date(Date.UTC(1899, 11, 30)).getTime()) / (24 * 60 * 60 * 1000);
  }

  sheet_from_array_of_arrays(data, opts) {
    let ws = {};
    let range = { s: { c: 10000000, r: 10000000 }, e: { c: 0, r: 0 } };
    for (let R = 0; R != data.length; ++R) {
      for (let C = 0; C != data[R].length; ++C) {
        if (range.s.r > R) range.s.r = R;
        if (range.s.c > C) range.s.c = C;
        if (range.e.r < R) range.e.r = R;
        if (range.e.c < C) range.e.c = C;
        let cell: any = { v: data[R][C] };
        if (cell.v == null) continue;
        let cell_ref = XLSX.utils.encode_cell({ c: C, r: R });

        if (typeof cell.v === 'number') cell.t = 'n';
        else if (typeof cell.v === 'boolean') cell.t = 'b';
        else if (cell.v instanceof Date) {
          cell.t = 'n';
          //cell.z = XLSX.SSF._table[14];
          cell.v = this.datenum(cell.v, null);
        }
        else cell.t = 's';

        ws[cell_ref] = cell;
      }
    }
    if (range.s.c < 10000000) ws['!ref'] = XLSX.utils.encode_range(range.s, range.e);
    return ws;
  }

  s2ab(s) {
    let buf = new ArrayBuffer(s.length);
    let view = new Uint8Array(buf);
    for (let i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xFF;
    return buf;
  }
}