"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.CSVLoader = void 0;
const text_1 = require("langchain/document_loaders/fs/text");
const papaparse_1 = __importDefault(require("papaparse"));
/**
 * A class that extends the TextLoader class. It represents a document
 * loader that loads documents from a CSV file. It has a constructor that
 * takes a `filePathOrBlob` parameter representing the path to the CSV
 * file or a Blob object, and an optional `options` parameter of type
 * `CSVLoaderOptions` or a string representing the column to use as the
 * document's pageContent.
 */
class CSVLoader extends text_1.TextLoader {
    constructor(filePathOrBlob, options) {
        super(filePathOrBlob);
        this.options = {};
        if (typeof options === 'string') {
            this.options = { column: options };
        }
        else {
            this.options = options ?? this.options;
        }
    }
    /**
     * A protected method that parses the raw CSV data and returns an array of
     * strings representing the pageContent of each document. It uses the
     * `papaparse` to parse the CSV data. If
     * the `column` option is specified, it checks if the column exists in the
     * CSV file and returns the values of that column as the pageContent. If
     * the `column` option is not specified, it converts each row of the CSV
     * data into key/value pairs and joins them with newline characters.
     * @param raw The raw CSV data to be parsed.
     * @returns An array of strings representing the pageContent of each document.
     */
    async parse(raw) {
        const { column, separator } = this.options;
        const { data: parsed, meta: { fields = [] } } = papaparse_1.default.parse(raw.trim(), {
            delimiter: separator,
            header: true
        });
        if (column !== undefined) {
            if (!fields.length) {
                throw new Error(`Unable to resolve fields from header.`);
            }
            let searchIdx = column;
            if (typeof column == 'number') {
                searchIdx = fields[column];
            }
            if (!fields.includes(searchIdx)) {
                throw new Error(`Column ${column} not found in CSV file.`);
            }
            // Note TextLoader will raise an exception if the value is null.
            return parsed.map((row) => row[searchIdx]);
        }
        return parsed.map((row) => fields.map((key) => `${key.trim() || '_0'}: ${row[key]?.trim()}`).join('\n'));
    }
}
exports.CSVLoader = CSVLoader;
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