guardz/dist/typeguards/isFileList.js

A simple and lightweight TypeScript type guard library for runtime type validation.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.isFileList = void 0;
const generateTypeGuardError_1 = require("./generateTypeGuardError");
/**
 * Checks if a value is a FileList object.
 *
 * This type guard is primarily useful in browser environments where FileList objects
 * are available (typically from file input elements). In Node.js environments, this will always return false.
 *
 * @param value - The value to check
 * @param config - Optional configuration for error handling
 * @returns True if the value is a FileList object, false otherwise
 *
 * @example
 * ```typescript
 * import { isFileList } from 'guardz';
 *
 * // Browser environment
 * const fileInput = document.querySelector('input[type="file"]');
 * if (fileInput?.files && isFileList(fileInput.files)) {
 *   // files is typed as FileList
 *   console.log('Number of files:', files.length);
 *   for (let i = 0; i < files.length; i++) {
 *     console.log('File:', files[i].name);
 *   }
 * }
 *
 * // With error handling
 * const data: unknown = getFileListData();
 * if (!isFileList(data, { identifier: 'uploadedFiles' })) {
 *   console.error('Invalid file list data');
 *   return;
 * }
 * // data is now typed as FileList
 * ```
 */
const isFileList = function (value, config) {
    // Check if we're in a browser environment where FileList is available
    const FileListConstructor = globalThis.FileList;
    if (typeof FileListConstructor === 'undefined') {
        // FileList is not available in this environment (e.g., Node.js)
        if (config) {
            config.callbackOnError((0, generateTypeGuardError_1.generateTypeGuardError)(value, config.identifier, 'FileList (not available in this environment)'));
        }
        return false;
    }
    if (!(value instanceof FileListConstructor)) {
        if (config) {
            config.callbackOnError((0, generateTypeGuardError_1.generateTypeGuardError)(value, config.identifier, 'FileList'));
        }
        return false;
    }
    return true;
};
exports.isFileList = isFileList;