chaining
v0.3.2
Published
Yet Another Chaining Library
Downloads
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Readme
Yet Another Javascript Chaining Library
Make callbacks simple, easy and readable.
Goals
- Strong error handling, keep Zalgo chained
- Deadly simple
- Complient with common deferred methods (node convention, promise standard and browser style)
Install
npm install chaining
You also need a es6 Promise library:
With when
require('chaining/src/es6/when');
With Q
require('chaining/src/es6/q');
Examples
var chain = new Chain();
chain.next(promiseForStuff());
chain.next(function (stuff) {
return promiseSomethingElse(stuff);
});
chain.process().then(function () {
console.log('end of process');
});
With parallelism and data flow:
var chain = new Chain();
chain.next(function () {
this.json = {};
}).fork([
'file1.json',
'file2.json',
'file3.json'
]).next(function (file, done) {
fs.readFile(file, done);
]).next(function (content) {
_.extend(this.json, JSON.pase(content));
});
chain.process().then(function () {
console.log('all files processed');
});
var chain = new Chain(function (id) {
return db.users.findOne({id: id});
})
.next(function (user) {
this.user = user;
return db.roles.find({user: this.user});
})
.next(function (roles) {
this.roles = roles;
if ('admin' in roles) {
this.user.admin = true;
}
return this.user.save();
});
chain.process(123);
var manager = new PackageManager();
var installer = new Chain();
installer.fork(function (depndencies) {
return this.depndencies;
})
.next(function (package) {
this.package = package;
return manager.preinstall(this.package);
})
.next(function () {
return manager.install(this.package);
})
.next(function () {
return manager.postinstall(this.package);
});
exports.install = function (depndencies) {
installer.process(depndencies).then(function () {
console.log('All installation completed');
}, function (err) {
console.error('Somethings went wrong...');
}, function (dep) {
console.log('Install ended for', dep.name);
});
};
API
Constructor()
Make a new chain.
.next(step)
Add a step to the sequence.
step
can be:
- a function that return a value
- a function that retrun a promise
- an async function that take a
done
callback - a value
- a promise (non sens ? promise can be resolve only once...)
.fork(iterable)
Fork and continue the sequence in parallel for each iterable item.
.join()
Wait for all forks and continue as a sigle sequence.
.process(value)
Start the sequence of steps with value
as initial value.
All steps are called in sequence after the previous step succeed and will share the same context (this
).
The sequence will be suspend when step
raise an exception or when step
return an rejected promise.
TODO
- Make it works in browser and publish on Bower
- Limit concurent forks
- add index for fork
- Progress notification for forks or steps ?
- Accept a node style callback for process
- Test fork with generators
- Error handling
- propate the number of arguments given by previous step (currently fixed to one)