@maukode/siesvi/dist/siesvi.loader.js

siesvi is CSV library that use typescript and provide CSV common functions from parsing, validation, to transformation.

"use strict";
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.FileLoader = void 0;
const stream_1 = require("stream");
const promises_1 = require("fs/promises");
class FileLoader extends stream_1.Readable {
    constructor(filePath, chunkSize = 64 * 1024) {
        super();
        this.fileHandle = null;
        this.position = 0;
        this.fileSize = 0;
        this.filePath = filePath;
        this.chunkSize = chunkSize;
    }
    _construct(callback) {
        return __awaiter(this, void 0, void 0, function* () {
            try {
                this.fileHandle = yield (0, promises_1.open)(this.filePath, 'r');
                const stats = yield this.fileHandle.stat();
                this.fileSize = stats.size;
                callback(null);
            }
            catch (error) {
                callback(error);
            }
        });
    }
    _read(_) {
        return __awaiter(this, void 0, void 0, function* () {
            if (!this.fileHandle) {
                this.destroy(new Error('File handle not initialized.'));
                return;
            }
            if (this.position >= this.fileSize) {
                this.push(null); // End of stream
                if (this.fileHandle) {
                    this.fileHandle.close();
                    this.fileHandle = null;
                }
                return;
            }
            const buffer = Buffer.alloc(Math.min(this.chunkSize, this.fileSize - this.position));
            try {
                const { bytesRead } = yield this.fileHandle.read(buffer, 0, buffer.length, this.position);
                if (bytesRead === 0) {
                    this.push(null); // End of stream
                    if (this.fileHandle) {
                        this.fileHandle.close();
                        this.fileHandle = null;
                    }
                    return;
                }
                this.position += bytesRead;
                this.push(buffer.subarray(0, bytesRead));
            }
            catch (error) {
                this.destroy(error);
                if (this.fileHandle) {
                    this.fileHandle.close();
                    this.fileHandle = null;
                }
            }
        });
    }
    _destroy(error, callback) {
        return __awaiter(this, void 0, void 0, function* () {
            if (this.fileHandle) {
                try {
                    yield this.fileHandle.close();
                    this.fileHandle = null;
                    callback(error);
                }
                catch (closeError) {
                    callback(error || closeError);
                }
            }
            else {
                callback(error);
            }
        });
    }
}
exports.FileLoader = FileLoader;