Change your console object a little bit useful

MAIN FUNCTION

• You can add date/time stamp before every log line.
• All console methods(info/error/warn/debug/log) are changed to prefix datetime stamp.
• One time use of 'require' changes global console object.

$ cat your.js

require('@gitul/konsole');
console.info("Hello, world!");

$ node your.js
2020-04-27 13:27:36.110 Hello, world?

That's it!

CUSTOMIZATION

You can customize konsole with 'set' method of konsole

var konsole = require('@gitul/konsole');

the konsole object is global.console itself, and which is added some more functions. so you can tweak these features with console.set method, but it is not recommend for compatibilities.

Change date/time format

We use a simple strftime function which implements %-format date/time value replacer. The default format of konsole is '%F %T.%f' (which means '%Y-%m-%d %H:%M:%S.%f'; e.g 2000-01-23 12:34:56.789). You can customize with konsole.set method.

var konsole = require('@gitul/konsole');
konsole.set('date-format', '%H:%M:%S');

console.debug("Hello world?");

-- run --

13:27:36 Hello, world?

Above example produces just only time related field (%H:%M:%S).

Add log caller location

Log locations sometimes help your debugging works, for e.g.,

function func1() {
    console.debug('CHECK 1');
    if (blah) {
        console.debug('CHECK 2');
        do_something();
    } else {
        console.debug('CHECK 3');
        do_anything();
    }
    for (var i=0; i<the.length; i++) {
        console.debug('CHECK 4', i);
        do_looping_works();
    }
    console.debug('CHECK 5');
}

func1();

Tracing with 'CHECK number' are good for debugging in runtime. Those lines are simply used for flow checking and deleted after debugging. The different numbers are needed for distinguishing source locations. To solve like this problem, just use as this.

var konsole = require('@gitul/konsole');
konsole.set('log-caller', true);

var blah=true;
function do_somthing(){};
function do_anything(){};
function do_looping_works(){};

function func1() {
    console.debug('CHECK');
    if (blah) {
        console.debug('CHECK');
        do_something();
    } else {
        console.debug('CHECK');
        do_anything();
    }
    for (var i=0; i<the.length; i++) {
        console.debug('CHECK', i);
        do_looping_works();
    }
    console.debug('CHECK');
}

func1();

Only we need is the reapeated line console.debug('CHECK');. This makes your debugging simple.

Let's test!

2020-04-28 18:45:37.817 CHECK at func1 (/home/user1/work/konsole/a.js:11:13)
2020-04-28 18:45:37.824 CHECK at func1 (/home/user1/work/konsole/a.js:13:17)
2020-04-28 18:45:37.824 CHECK 0 at func1 (/home/user1/work/konsole/a.js:20:17)
2020-04-28 18:45:37.825 CHECK 1 at func1 (/home/user1/work/konsole/a.js:20:17)
2020-04-28 18:45:37.825 CHECK 2 at func1 (/home/user1/work/konsole/a.js:20:17)
2020-04-28 18:45:37.825 CHECK at func1 (/home/user1/work/konsole/a.js:23:13)

Strip caller's common path

As you see above example, the project root path is not necessary, so we can specify with strip-prefix to strip out the paths.

var konsole = require('@gitul/konsole');
konsole.set('log-caller', true);
konsole.set('strip-prefix', __dirname );

... (same with above example) ...

Run again!

2020-04-28 20:13:40.269 CHECK at func1 (a.js:12:13)
2020-04-28 20:13:40.275 CHECK at func1 (a.js:14:17)
2020-04-28 20:13:40.276 CHECK 0 at func1 (a.js:21:17)
2020-04-28 20:13:40.276 CHECK 1 at func1 (a.js:21:17)
2020-04-28 20:13:40.277 CHECK 2 at func1 (a.js:21:17)
2020-04-28 20:13:40.277 CHECK at func1 (a.js:24:13)

This is simpler and clear.

Call stack level

If you need more than one frame, you can set calling log level.

var konsole = require('@gitul/konsole');
konsole.set('log-caller', true);
konsole.set('log-caller-frames', 2);
konsole.set('strip-prefix', __dirname );

This will log top most two levels from call stack.

NOTICE: We use 'new Error().stack' mechanism for checking call stack, and which is expensive way, so it is recommended to be removed in production mode.