See CHANGE LOG for notable changes.

Yuan-DEV

yuan-dev makes it easy to return something different for debug.

Quick Start

For example, normally we will start the http server listening to port 80, however, we may want it listening to port 8080 instead when debugging:

// index.js

const http = require('http');
const dev = require('yuan-dev');

const server = http.createServer((req, res) => {
	res.end('Hello Yuan DEV!');
});

var port = dev('LOCAL', 8080, 80);
server.listen(port);

By default, the port will be 80. While run with env DEV set, port 8080 will be used:

DEV=LOCAL node index

Define Values For More Dev Modes

Of course, We can also do it by the way more ordinary:

var port = dev('LOCAL') ? 8080 : 80;

Or, to accomplish more, we can define different values:

var port = dev({ LOCAL: 8080, FAT: 8088, UAT: 3000 }, 80);

The, we will get:

# port 8088
DEV=FAT node index

# port 3000
DEV=UAT node index

The DEV environment variable SHOULD be comma-delimited names, e.g.

DEV=FAT,INFO node index

About Returned Values

Although the values used in yuan-dev are generally simple scalars (number, string or boolean), they may also be anything including function object:

var fnGetPort = dev({
	LOCAL : () => 8080 },
	FAT   : () => 8088 },
	UAT   : () => 3000 }
}, () => 80 );

var port = fnGetPort();

Do Something On Dev Mode

And, if you want do something special on dev mode, dev.action() is helpful:

var port = dev({
	LOCAL: dev.action(() => {
		console.log('The server will listen to 8080.');
		return 8080;
	}
}, 80);

dev.action() will not do play outside of dev().

However, another method is offered:

//  Run immediately on DEV mode.
dev.run(() => {
	console.log('We are under DEV mode now.');
});

// Equals to,
if (dev()) {
	console.log('We ares under DEV mode now.');
}

// Of course, we can do something ONLY on special DEV mode.
dev.run('LOCAL', () => {
	console.log('We are under DEV mode (LOCAL) now.');
});

// In more complex cases, we can use functions similiar to logic control statements.
// if() ... elif()/elseif() ... else()
dev
	.if('LOCAL', () => {
		console.log('We are under DEV mode (LOCAL) now.');
	})
	.elseif('FAT', () => {
		console.log('We are under DEV mode (FAT) now.');
	})
	.else(() => {
		console.log('We ares NOT under DEV mode (LOCAL) or DEV mode (FAT) now.');
		console.log('ATTENTION: But maybe we are under some DEV mode other than LOCAL or FAT.');
	});

dev
	.if(() => {
		console.log('We are under DEV mode.');
	})
	.else(() => {
		console.log('We are NOT under any DEV mode.');
	})

Not everybody like this syntax sugar, but I think it is more elegant using dev.if().else() than the general if ... else ... control statement.

more

Run the next commands to install devDependencies and run mocha unit test:

npm install
npm test