a transform for browserify, which allows the replacement of (undeclared/implicit) CONSTANTS with values based on an external configuration
npm install extern-constantifyextern-constantify
==================
 
Browserify transform that allows does in-place replacement of global constants, without having to declare them or import them at every occurence.
`` bash`
browserify -t extern-constantify entry.js > bundle.js
For example, suppose you have different classes/objects in your project communicating by events/messages:
` javascript
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:
` javascript
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 file
` javascript``
{
"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.