@aws-amplify/core/src/Logger/ConsoleLogger.ts

Core category of aws-amplify

/*
 * Copyright 2017-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with
 * the License. A copy of the License is located at
 *
 *     http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
 * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
 * and limitations under the License.
 */

import { Logger } from './logger-interface';

const LOG_LEVELS = {
	VERBOSE: 1,
	DEBUG: 2,
	INFO: 3,
	WARN: 4,
	ERROR: 5,
};

/**
 * Write logs
 * @class Logger
 */
export class ConsoleLogger implements Logger {
	name: string;
	level: string;

	/**
	 * @constructor
	 * @param {string} name - Name of the logger
	 */
	constructor(name, level = 'WARN') {
		this.name = name;
		this.level = level;
	}

	static LOG_LEVEL = null;

	_padding(n) {
		return n < 10 ? '0' + n : '' + n;
	}

	_ts() {
		const dt = new Date();
		return (
			[this._padding(dt.getMinutes()), this._padding(dt.getSeconds())].join(
				':'
			) +
			'.' +
			dt.getMilliseconds()
		);
	}

	/**
	 * Write log
	 * @method
	 * @memeberof Logger
	 * @param {string} type - log type, default INFO
	 * @param {string|object} msg - Logging message or object
	 */
	_log(type: string, ...msg) {
		let logger_level_name = this.level;
		if (ConsoleLogger.LOG_LEVEL) {
			logger_level_name = ConsoleLogger.LOG_LEVEL;
		}
		if (typeof (<any>window) !== 'undefined' && (<any>window).LOG_LEVEL) {
			logger_level_name = (<any>window).LOG_LEVEL;
		}
		const logger_level = LOG_LEVELS[logger_level_name];
		const type_level = LOG_LEVELS[type];
		if (!(type_level >= logger_level)) {
			// Do nothing if type is not greater than or equal to logger level (handle undefined)
			return;
		}

		let log = console.log.bind(console);
		if (type === 'ERROR' && console.error) {
			log = console.error.bind(console);
		}
		if (type === 'WARN' && console.warn) {
			log = console.warn.bind(console);
		}

		const prefix = `[${type}] ${this._ts()} ${this.name}`;

		if (msg.length === 1 && typeof msg[0] === 'string') {
			log(`${prefix} - ${msg[0]}`);
		} else if (msg.length === 1) {
			log(prefix, msg[0]);
		} else if (typeof msg[0] === 'string') {
			let obj = msg.slice(1);
			if (obj.length === 1) {
				obj = obj[0];
			}
			log(`${prefix} - ${msg[0]}`, obj);
		} else {
			log(prefix, msg);
		}
	}

	/**
	 * Write General log. Default to INFO
	 * @method
	 * @memeberof Logger
	 * @param {string|object} msg - Logging message or object
	 */
	log(...msg) {
		this._log('INFO', ...msg);
	}

	/**
	 * Write INFO log
	 * @method
	 * @memeberof Logger
	 * @param {string|object} msg - Logging message or object
	 */
	info(...msg) {
		this._log('INFO', ...msg);
	}

	/**
	 * Write WARN log
	 * @method
	 * @memeberof Logger
	 * @param {string|object} msg - Logging message or object
	 */
	warn(...msg) {
		this._log('WARN', ...msg);
	}

	/**
	 * Write ERROR log
	 * @method
	 * @memeberof Logger
	 * @param {string|object} msg - Logging message or object
	 */
	error(...msg) {
		this._log('ERROR', ...msg);
	}

	/**
	 * Write DEBUG log
	 * @method
	 * @memeberof Logger
	 * @param {string|object} msg - Logging message or object
	 */
	debug(...msg) {
		this._log('DEBUG', ...msg);
	}

	/**
	 * Write VERBOSE log
	 * @method
	 * @memeberof Logger
	 * @param {string|object} msg - Logging message or object
	 */
	verbose(...msg) {
		this._log('VERBOSE', ...msg);
	}
}