simple "reverse-connect.js" contorl flow library
npm install usablesimple "reverse-connect.js" contorl flow library
usable
======
install
-------
npm install usable
installation
------------
var usable = require ('usable') ();
each middleware binds on filter and executes in insertion order
context-safeness
----------------
each call of each passed to usable function is context safe, so you can use it with more complicated modules, such as ORM or redis.
but, unfortunalty, this techniqueue limits number of callback arguments up to 7, so be careful.
dependency
----------
only dependensy of usable is sift module, that used for mongodb-like filtering
if you totally sure, that you no need this functionality, feel free to remove sift from node_modules, it will not break other kind of filters.
usage
-----
#### functional filter ####
usable (function filter (o) {
return o.val < 0.5;
}, function middleware (o, next) {
o.val = Math.round (val);
next ();
});
usable ({
o: Math.random()
}, function (err, o) {
console.log (o.a);
});
#### object filter ####
monogdb-like api
usable.use ({
a: {$exists:true}
}, function (o, next) {
if (!o.a) {
next (new Error ("error!"));
} else {
next ();
}
});
usable ({
a: "value"
}, function (err, o) {
if (err) {
console.error (err);
} else {
console.log (o.a)
}
});
#### string and RegExp filters ####
if a string is a only one argument to usable instance, then it compiles to regexp and behave like regexp
usable.use ("foo", function (text, next) {
console.log (text);
next ();
});
usable ("bar foobaz", function (err, text) {
console.log (text);
});
#### more ####
when you instantiate usable function, you can pass it optional global handlers.
each global handler will be called in order of add and runs each time
var usable = require ('usable') (function (next) {
// some code here
next ();
}, function (next) {
// some other code here
next ();
});
var usable = require ('usable') ([function (next) {
// some code here
next ();
}, function (next) {
// some other code here
next ();
}])
of course, it's not only one way to use multiple global handlers. just call use with array of functions
usable.use ([function..., function...]);
but, if you add some filter before array of functions, it's ok too:
usable.use (function..., [function..., function...]);