office-text-extractor-browser/build/parsers/excel.js

Fork of office-text-extractor with unreleased changes that include browser support

// source/parsers/excel.ts
// The text extracter for Excel files.
import Xlsx, { utils as sheetUtils } from 'xlsx';
import { dump as convertToYaml } from 'js-yaml';
const parseExcelFile = Xlsx.read;
const convertSheetToJson = sheetUtils.sheet_to_json;
export class ExcelExtractor {
    constructor() {
        /**
         * The type(s) of input acceptable to this method.
         */
        this.mimes = ['application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'];
        /**
         * Extract text from a Excel file if possible.
         *
         * @param payload The input and its type.
         * @returns The text extracted from the input.
         */
        this.apply = async (input) => {
            // Read the contents of the Excel file and convert them to JSON.
            const workbook = parseExcelFile(input, { type: 'buffer' });
            // Get the names of all the sheets, loop through the sheets and return
            // nicely formatted text.
            const sheets = workbook.SheetNames;
            let formattedText = '';
            for (const sheet of sheets) {
                // Add the sheet separator to indicate a new sheet has started.
                formattedText += '===\n';
                const sheetJson = convertSheetToJson(workbook.Sheets[sheet]);
                for (const row of sheetJson) {
                    formattedText += '---\n';
                    formattedText += convertToYaml(row)
                        // If the column header is empty, the YAML converter replaces it with '__EMPTY'.
                        // Replace that with just underscore + the column number instead.
                        .replace(/__EMPTY*:/g, ':')
                        .replace(/__EMPTY_\d?:/g, ':');
                }
            }
            return formattedText;
        };
    }
}