Day Log Savings
Table Of Contents
About
Day Log Savings is a simple, zero dependencies, Node.js logger that lets you log things in organized, day rotating files.
The name is a play on words of daylight savings, which started when this module was first created.
Each day, a new log file is created, that file is then categorised into month and year folders.
By default, query's are logged like so: [<time>] [<prefix>] <input> but you can customize this by using the functions options or changing the defaults. Those query's are then written into log files and saved at <project root>/logs/<year>/<month>/<day>.log. For example: /logs/2020/11/27.log.
Installation
npm install day-log-savings
Test
npm test
Write
Writes an input to the logs, customizable with options.
Usage
Function: <logger>.write(<input>, [options]);
Returns: The string which was just logged.
Input {any}: The input which you want to be logged.
Options {object}: {
-
Prefix {string}: The prefix which appears before the log input, case sensitive. In case of error, prefix is automatically changed to 'ERROR'. Defaults to 'LOG'.
-
Format {object}: { Change the format of the dates, timestamps and the log message itself. Use
%<option>to define where within the string you want said option to appear.- Message {string}: The format in which your input appears in the logs. Options are '%time', '%date', '%prefix' and '%message'. Defaults to '[%time] [%prefix] %message'.
- Time {string}: The format which the timestamps are displayed in. Options are '%hour', '%minute' and '%second'. Defaults to '%hour:%minute:%second'.
- Date {string}: The format which the date are displayed in. Does not change the path to where logs are saved. Options are '%year', '%month' and '%day'. Defaults to '%year/%month/%day'.
}
- Length {number}: The maximum length the input can be before being put on a new line. Defaults to '100'.
- Console {boolean}: Whether or not to log the query in the console along with the log file. Errors will always be logged. Defaults to 'false'.
- Stringify {boolean}: If the input is an instance of 'Object', then JSON.stringify() it . Defaults to 'true'.
- Stack {boolean}: If the input is an instance of 'Error', then use the stack property of it. Defaults to 'true'.
}
Examples
logger.write('Input using the default options.');
// [00:00:00] [LOG] Input using the default options.
logger.write('Has a custom prefix.', { prefix: 'cUsToM' });
// [00:00:00] [cUsToM] Has a custom prefix.
logger.write('Custom date, time and message format.', { format: { message: '[%date %time] [%prefix]: %message', date: '%day/%month/%year', time: '%hour.%minute.%second' } });
// [27/11/2020 00.00.00] [LOG]: Custom date, time and message format.
logger.write('Max first line input length reached.', { length: 1 });
// [00:00:00] [LOG]
// Max first line input length reached.
logger.write("This will be logged in the console and log file.", { console: true });
// Console & Log File:
// [00:00] [LOG] This will be logged in the console and log file.
logger.write(new Error('This error will not be stacked.'), { stack: false });
// [00:00:00] [ERROR] This error will not be stacked.
logger.write({ thisObjectWill: 'not be stringified' }, { stringify: false });
// [00:00:00] [LOG] [object Object]Read
Reads and outputs the last x number lines from the bottom of a log file.
Usage
Function: <logger>.read([options]);
Returns: The last x number of lines of a log file.
Options {object}: {
- Path {string}: The path, formatted as 'year/month/day', to the log file which you want to read. Defaults to to todays date.
- Lines {number}: The number of lines you want to read. Defaults to '15'.
- Array {boolean}: Whether you want the output in an array (where one line equal one item) or not. Defaults to 'false'.
- Blanks {boolean}: Whether or not to include blank lines in the output, both string and array. Defaults to 'true'.
}
Examples
logger.read();
// Returns a string containing the last 15 lines of todays log file.
logger.read({ path: '2020/11/27', lines: 5 });
// Returns a string containing the last 5 lines of the 27th of November 2020 log file.
logger.read({ array: true, blanks: false });
// Returns an array containing the last 15 lines of todays log file with all the blank lines removed.Remove
Deletes a log file.
Usage
Function: <logger>.remove([path]);
Returns: The path, formatted as 'year/month/day', to the file that was just deleted.
Path {string}: The path, formatted as 'year/month/day', to the log file which you want to delete. Defaults to to todays date.
logger.remove();
// Deletes todays log file.
logger.remove('2020/11/27');
// Deletes the 27th of November 2020 log file.Defaults
Change the defaults for one of the functions that the module has.
Usage
Function: <logger>.defaults(<method>, [options]);
Returns: The new defaults object of the chosen function.
Method {string}: The name of the function you want to change the defaults for. Example: 'write', 'read'.
Options {object}: The new defaults which you want to set.
Examples
logger.defaults('write', { prefix: 'INFO', format: '%date %time %prefix: %message' });
// Changes the default prefix to 'INFO' and the format to '%date %time %prefix: %message'.
logger.defaults('read', { array: true, blanks: false });
// Ensures that the read function returns an array and removes all the blank lines.
logger.defaults('root', { path: `${process.cwd()}/achieve/logs` });
// Changes the default log root from '<project root>/logs' to '<project root>/achieve/logs'.