@aws-amplify/core/src/JS.ts

Core category of aws-amplify

// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

const MIME_MAP = [
	{ type: 'text/plain', ext: 'txt' },
	{ type: 'text/html', ext: 'html' },
	{ type: 'text/javascript', ext: 'js' },
	{ type: 'text/css', ext: 'css' },
	{ type: 'text/csv', ext: 'csv' },
	{ type: 'text/yaml', ext: 'yml' },
	{ type: 'text/yaml', ext: 'yaml' },
	{ type: 'text/calendar', ext: 'ics' },
	{ type: 'text/calendar', ext: 'ical' },

	{ type: 'image/apng', ext: 'apng' },
	{ type: 'image/bmp', ext: 'bmp' },
	{ type: 'image/gif', ext: 'gif' },
	{ type: 'image/x-icon', ext: 'ico' },
	{ type: 'image/x-icon', ext: 'cur' },
	{ type: 'image/jpeg', ext: 'jpg' },
	{ type: 'image/jpeg', ext: 'jpeg' },
	{ type: 'image/jpeg', ext: 'jfif' },
	{ type: 'image/jpeg', ext: 'pjp' },
	{ type: 'image/jpeg', ext: 'pjpeg' },
	{ type: 'image/png', ext: 'png' },
	{ type: 'image/svg+xml', ext: 'svg' },
	{ type: 'image/tiff', ext: 'tif' },
	{ type: 'image/tiff', ext: 'tiff' },
	{ type: 'image/webp', ext: 'webp' },

	{ type: 'application/json', ext: 'json' },
	{ type: 'application/xml', ext: 'xml' },
	{ type: 'application/x-sh', ext: 'sh' },
	{ type: 'application/zip', ext: 'zip' },
	{ type: 'application/x-rar-compressed', ext: 'rar' },
	{ type: 'application/x-tar', ext: 'tar' },
	{ type: 'application/x-bzip', ext: 'bz' },
	{ type: 'application/x-bzip2', ext: 'bz2' },
	{ type: 'application/pdf', ext: 'pdf' },
	{ type: 'application/java-archive', ext: 'jar' },
	{ type: 'application/msword', ext: 'doc' },
	{ type: 'application/vnd.ms-excel', ext: 'xls' },
	{ type: 'application/vnd.ms-excel', ext: 'xlsx' },

	{ type: 'message/rfc822', ext: 'eml' },
];

export const isEmpty = (obj = {}) => Object.keys(obj).length === 0;

export const sortByField = (list, field, dir) => {
	if (!list || !list.sort) {
		return false;
	}

	const dirX = dir && dir === 'desc' ? -1 : 1;
	list.sort(function(a, b) {
		const a_val = a[field];
		const b_val = b[field];

		if (typeof b_val === 'undefined') {
			return typeof a_val === 'undefined' ? 0 : 1 * dirX;
		}

		if (typeof a_val === 'undefined') {
			return -1 * dirX;
		}

		if (a_val < b_val) {
			return -1 * dirX;
		}
		if (a_val > b_val) {
			return 1 * dirX;
		}

		return 0;
	});

	return true;
};

export const objectLessAttributes = (obj, less) => {
	const ret = Object.assign({}, obj);
	if (less) {
		if (typeof less === 'string') {
			delete ret[less];
		} else {
			less.forEach(attr => {
				delete ret[attr];
			});
		}
	}

	return ret;
};

export const filenameToContentType = (
	filename,
	defVal = 'application/octet-stream'
) => {
	const name = filename.toLowerCase();

	const filtered = MIME_MAP.filter(mime => name.endsWith('.' + mime.ext));
	return filtered.length > 0 ? filtered[0].type : defVal;
};

export const isTextFile = contentType => {
	const type = contentType.toLowerCase();
	if (type.startsWith('text/')) {
		return true;
	}
	return (
		'application/json' === type ||
		'application/xml' === type ||
		'application/sh' === type
	);
};

export const generateRandomString = () => {
	let result = '';
	const chars =
		'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
	for (let i = 32; i > 0; i -= 1) {
		result += chars[Math.floor(Math.random() * chars.length)];
	}
	return result;
};

export const makeQuerablePromise = promise => {
	if (promise.isResolved) return promise;

	let isPending = true;
	let isRejected = false;
	let isFullfilled = false;

	const result = promise.then(
		data => {
			isFullfilled = true;
			isPending = false;
			return data;
		},
		e => {
			isRejected = true;
			isPending = false;
			throw e;
		}
	);

	result.isFullfilled = () => isFullfilled;
	result.isPending = () => isPending;
	result.isRejected = () => isRejected;

	return result;
};

export const isWebWorker = () => {
	if (typeof self === 'undefined') {
		return false;
	}
	const selfContext = self as { WorkerGlobalScope? };
	return (
		typeof selfContext.WorkerGlobalScope !== 'undefined' &&
		self instanceof selfContext.WorkerGlobalScope
	);
};

export const browserOrNode = () => {
	const isBrowser =
		typeof window !== 'undefined' && typeof window.document !== 'undefined';
	const isNode =
		typeof process !== 'undefined' &&
		process.versions != null &&
		process.versions.node != null;

	return {
		isBrowser,
		isNode,
	};
};

/**
 * transfer the first letter of the keys to lowercase
 * @param {Object} obj - the object need to be transferred
 * @param {Array} whiteListForItself - whitelist itself from being transferred
 * @param {Array} whiteListForChildren - whitelist its children keys from being transferred
 */
export const transferKeyToLowerCase = (
	obj,
	whiteListForItself = [],
	whiteListForChildren = []
) => {
	if (!isStrictObject(obj)) return obj;
	const ret = {};

	for (const key in obj) {
		if (obj.hasOwnProperty(key)) {
			const transferedKey = whiteListForItself.includes(key)
				? key
				: key[0].toLowerCase() + key.slice(1);

			ret[transferedKey] = whiteListForChildren.includes(key)
				? obj[key]
				: transferKeyToLowerCase(
						obj[key],
						whiteListForItself,
						whiteListForChildren
				  );
		}
	}

	return ret;
};

/**
 * transfer the first letter of the keys to lowercase
 * @param {Object} obj - the object need to be transferred
 * @param {Array} whiteListForItself - whitelist itself from being transferred
 * @param {Array} whiteListForChildren - whitelist its children keys from being transferred
 */
export const transferKeyToUpperCase = (
	obj,
	whiteListForItself = [],
	whiteListForChildren = []
) => {
	if (!isStrictObject(obj)) return obj;
	const ret = {};

	for (const key in obj) {
		if (obj.hasOwnProperty(key)) {
			const transferredKey = whiteListForItself.includes(key)
				? key
				: key[0].toUpperCase() + key.slice(1);

			ret[transferredKey] = whiteListForChildren.includes(key)
				? obj[key]
				: transferKeyToUpperCase(
						obj[key],
						whiteListForItself,
						whiteListForChildren
				  );
		}
	}
	return ret;
};

/**
 * Return true if the object is a strict object
 * which means it's not Array, Function, Number, String, Boolean or Null
 * @param obj the Object
 */
export const isStrictObject = obj => {
	return (
		obj instanceof Object &&
		!(obj instanceof Array) &&
		!(obj instanceof Function) &&
		!(obj instanceof Number) &&
		!(obj instanceof String) &&
		!(obj instanceof Boolean)
	);
};