extern-constantify

extern-constantify

Browserify transform that allows does in-place replacement of global constants, without having to declare them or import them at every occurence.

Installation

Usage

browserify -t extern-constantify entry.js > bundle.js

Example

For example, suppose you have different classes/objects in your project communicating by events/messages:

var Sender = function () {
	this.emit('begin');
	//do some stuff, reporting progress
	this.emit('busy', progress);
	//finalize and report success
	this.emit('done');
};

var Receiver = function (sender) {
	sender.on('begin', function(data) {
		node.innerHTML = 'Starting...';
	});
	sender.on('busy', function(data) {
		node.innerHTML = 'Work is ' + data + '% complete';
	});
	sender.on('done', function(data) {
		node.innerHTML = 'Work is done';
	});
};

Now suppose you later decide to change the names of these events to start, progress and end. You would have to look for the various occurences of the original literal strings in your code and replace them accordingly. This introduces a lot of room for error. Instead you could write this:

var Sender = function () {
	this.emit(BEGIN_EVENT);
	//do some stuff, reporting progress
	this.emit(BUSY_EVENT, progress);
	//finalize and report success
	this.emit(END_EVENT);
};

var Receiver = function (sender) {
	sender.on(BEGIN_EVENT, function(data) {
		node.innerHTML = 'Starting...';
	});
	sender.on(BUSY_EVENT, function(data) {
		node.innerHTML = 'Work is ' + data + '% complete';
	});
	sender.on(END_EVENT, function(data) {
		node.innerHTML = 'Work is done';
	});
};

and provide the following configuration in your package.json file

{
  "extern-constantify": {
	"BEGIN_EVENT": "begin",
	"BUSY_EVENT": "busy",
	"END_EVENT": "done"
  }
}

The aforementioned change would then only require one edit in your configuration instead of the multiple edits that were previously required.

The matching happens case-sensitively, so you can avoid naming conflicts by uppercasing all characters of a constant name. This is the recommended coding style, however it is not mandatory.

License

MIT