Log activities, showing the time it takes to complete them.

Track how long certain activities take in your application.

Think of it is a more powerful and expressive console.time, one that lets you customize not only what is logged out but also where it goes. You can pipe messages to console.log, process.stdout, or write to the file system however you like!

Super inspired by react-native's Activity module.

$ npm install --save activity-logger

Basic usage.

const activity = require('activity-logger');

var ovenActivity = activity.start('Heating up the oven.');
// logs -> 'Heating up the oven';

setTimeout(function() {
	activity.end(ovenActivity);
	// logs -> 'Heating up the oven (1234ms)'
}, 1234);

You can customize what the output looks like.

activity.setStartFormatter(function(activity) {
	return '[' + activity.id + '] ' + activity.message + ' @ ' +
		new Date(activity.timestamps[0]).toLocaleTimeString();
});

var activityId = activity.start('Booting up');
// logs -> '[2] Booting up @ 9:51:26 AM'

activity.setEndFormatter(function(activity) {
	return '[' + activity.id + '] ' + activity.message + ' @ ' +
		new Date(activity.timestamps[0]).toLocaleTimeString() +
		' - COMPLETED (' + (activity.timestamps[1] - activity.timestamps[0]) + 'ms)';
});

setTimeout(function() {
	activity.end(activityId);
	// logs -> '[2] Booting up @ 9:51:26 AM - COMPLETED (23ms)'
}, 23);

And you can change where the output is sent!

activity.setOutputHandlers(function(message) {
	fs.appendFileSync('./log.txt', message, 'utf8');
});

// Now every message is appended to our log file.

Returns the activityId you can later use to end the activity. Logs out to console that the activity has started.

Type: string

The message you want outputted.

Ends the activity and returns the Activity object. Logs out to the console the activity ended, showing the time it took to complete.

Type: number

The id of the activity we want to end.

Returns the activityId you can later use to end the activity. Does not create any timestamp, just registers a new activity.

Type: string

The message you want outputted.

Adds a new timestamp to the Activity's array of timestamps.

Type: number

The id of the activity.

Returns Activity object after removing it from internal cache of activities. Does not modify Activity object at all.

Type: number

The id of the activity.

Disable output.

Enable output.

Change how start events are outputted.

Type: function

Formatter is given an activity object. It must return a string as that is given to each function in outputHandlers array.

activity

{
	"id": 21,
	"message": "Message string given from activity.start",
	"timestamps": [1453692902523]
}

Change how end events are outputted.

Type: function

Formatter is given an activity object. It must return a string as that is given to each function in the outputHandlers array. In the end event the timestamps array has a second value to calculate the time spread.

activity

{
	"id": 21,
	"message": "Message string given from activity.start",
	"timestamps": [1453692902523, 1453692905599]
}

Returns all outputHandlers.

Overwrite the existing outputHandlers array.

Type: ...function

A variable number of new functions to set as outputHandlers.

Add one handler to the outputHandlers array.

Type: function

MIT © Harry Wolff