README
Common
A utility module for both node.js and the browser.
It is available through npm:
npm install common
Or as minified js file for the browser:
<script src='common.min.js'></script>
This module among other things contains a fork of step that also provides error handling
common.step([
function(next) { // next is the last argument, except in the last handler
fs.readFile(__filename, 'utf-8', next);
},
function(file) {
console.log(file);
}
], function(err) {
// any error received in a callback will be forwarded here
});
It also contains a shortcut to the EventEmitter
prototype and a compatible implementation of this for the browser.
var MyEmitter = common.emitter(function() {
this.foo = 42;
});
var me = new MyEmitter();
me.emit('foo', me.foo); // emits 'foo',42
There is also a more general method for extending prototypes called extend
:
// this prototype is the same as above
var MyEmitter = common.extend(events.EventEmitter, function() {
this.foo = 42;
});
If you want to use futures you can use the future
function to create a future:
var fut = common.future();
fut.get(function(val) {
console.log(val);
});
setTimeout(function() {
fut.put(42); // results in the previous .get being called and all future .get's will be called synchroniously
}, 1000)
To do string formatting you can use format
:
// you can parse the arguments to a pattern one by one
common.format('define {0} here', 'pattern'); // returns 'define pattern here'
// or as a map or array
common.format('define {foo} here', {foo:'pattern'}); // same as above
There is a log
method that just accepts the does the same as format
except it prints out the result using console.log
if available
To generate a simple weak symbols (often used when generating keys for a map) use gensym
common.gensym() // returns 's0'
common.gensym() // returns 's1'
If you instead of a weak symbol need a strong one use uuid
:
common.uuid(); // returns a strong id, ex: ngDl6IdovME9JKvIxgED0FK1kzURxfZaCq48-0
Common can also encode integers into alphanumerical notation using encode
:
common.encode(1000); // returns G8
To ensure that a method cannot be called more than once you can use the once
function:
var fn = common.once(function() {
console.log('hello');
});
fn(); // prints hello
fn(); // does nothing
Besides the above common implements two of the utilities mentioned in The Good Parts, memoizer
and curry
.