Fluid.js is a simple, fluent, API that automatically manages callbacks of asynchronous code.
Without fluid :-
fs.readFile("./input1.txt", function(err, input1Buffer) {
if (err) {console.log(err)} else {
fs.readFile("./input2.txt", function(err, input2Buffer) {
if (err) {console.log(err)} else {
var content = input1Buffer.toString() + input2Buffer.toString();
fs.writeFile("./output.txt", content, function(err) {
if (err) {console.log(err)} else {
//do something
}
});
}
});
}
});
With fluid :-
$f(fs).readFile("./input1.txt").readFile("./input2.txt")
.writeFile("./output1.txt", $f("this.readFile[0].toString() + this.readFile[1].toString()"))
.go(function(err, values) {
if (err) {console.log(err)} else {
//do something
}
});
Any error handling is managed in the "go" callback and all callback return values are available for usage.
NOTE: Fluid.js currently only supports methods that take a callback as the last argument:-
function(options, callback) -> callback(err, result)
function(arg1, arg2, ..., callback) -> callback(err, result)
etc...
var $f = require("fluid");
var myFirstObj = {
doSomething : function(options, callback) {
//do something
callback(err, result);
},
doSomethingElse : function(options, callback) {
//do something else
callback(err, result);
}
};
var mySecondObj = {
doSomethingMore : function(options, callback) {
//do something more
callback(err, result);
}
};
Note: series is the default flow control mode, so it can be ommitted
$f(myFirstObj).doSomething(/* args */).doSomethingElse(/* args */)
.with(mySecondObj).doSomethingMore(/* args */)
.go(function(err, results) {
// results is now an array of return values from each method callback
});
$f().series()
.with(myFirstObj)
.doSomething(/* args */)
.doSomethingElse(/* args */)
.with(mySecondObj)
.doSomethingMore(/* args */)
.go(function(err, results) {
// results is now an array of return values from each method callback
});
$f()
.series()
.with(myFirstObj)
.doSomething(/* args */)
.doSomethingElse(/* args */)
.parallel()
.with(mySecondObj)
.doSomethingMore(/* args */)
.doSomethingMorer(/* args */)
.doSomethingMorerer(/* args */)
.go(function(err, results) {
// results is now an array of return values from each method callback
});
To install with node package manager:
npm install fluid
To test with node package manager:
npm test
Releases are available for download from GitHub.
### fluid([context])
Creates a new fluent interface (fluid context), optionally wrapping an initial user specifed application context.
Note, if desired, the initial context can be left blank and applied later using the with command.
Arguments
- context - An initial application context to wrap with fluent methods.
- Returns a new fluid context.
Example
$f(fs).readFile("./test.txt")
/* .etc.etc... */
.go(function(err, res) { /* finished */ }
### with(context)
Switches the current application context to the one specified.
Note, The context can be switch as many times as required. Useful when working with multiple libraries.
Arguments
- context - An application context to wrap.
- Returns the current fluid context.
Example
$f(myObj).doSomething(/* args */)
.with(myObj2).doSomethingElse(/* args */)
/* .etc.etc... */
.go(function(err, res) { /* finished */ });
### series()
Creates a new group of method calls that will be executed in series. Multiple groups with different flow control types can be used together, and will themselves be executed in series when the go command is called.
Note, This is the default execution mode when a new fluid context has been created.
Arguments
- Returns the current fluid context.
Example
$f(myObj).series()
.doSomething(/* args */)
.doSomethingElse(/* args */)
/* .etc.etc... */
.go(function(err, res) { /* finished */ });
### parallel()
Creates a new group of method calls that will be executed in parallel. Multiple groups with different flow control types can be used together, and will themselves be executed in series when the go command is called.
Note, see the Async module for more information on the difference between series and parallel flow controls.
Arguments
- Returns the current fluid context.
Example
$f(myObj).parallel()
.doSomething(/* args */)
.doSomethingElse(/* args */)
/* .etc.etc... */
.go(function(err, res) { /* finished */ });
### info(options)
Provides a way to explicitly name callback values on the result. Also allows decorating errors with extra detail.
Arguments
- options - Options for providing explicit detail for result
- name - String. Specifies a name for the callback return value on the result.
- error - String. Specifies extra detail to decorate any error raised.
Example
$f(fs)
.info({name : "test1"}).readFile("./test1.txt")
.info({name : "test2"}).readFile("./test2.txt")
.go(function(err, result) {
/*
result:-
{
test1 : [<Buffer>],
test2 : [<Buffer>]
}
*/
});
You can also use the short hand:-
$f(fs)
({name : "test1"}).readFile("./test1.txt")
({name : "test2"}).readFile("./test2.txt")
.go(function(err, result) {});
Note, there is no '.' before the '('. The fluid context itself wraps the info function.
### custom(customFunction(callback))
Creates a new custom task that is added to the existing group. The custom task must invoke the callback provided when finished processing.
Arguments
- customFunction(callback) - Some custom code that will receive a callback to be invoked upon completion.
- callback - Function. A callback to invoke when custom code has completed.
Example
$f(fs)
.readFile("./test1.txt")
.readFile("./test2.txt")
.custom(function(callback) {
callback(null, this.readFile[0].toString() + this.readFile[1].toString());
})
.writeFile("./output.txt", $f("this.custom[0]"))
.go(function(err, result) {});
### self()
If the context being wrapped is a function itself, it can be invoked using the self method.
Example
var myFunc = function(arg, callback) {
callback(null, arg + 1);
}
$f(myFunc)
.self(1)
.self(2)
.go(function(err, result) {});
### go([options,] callback)
Executes all queued function calls against their registered application contexts, then invokes the specified callback when completed, or any of the methods error.
If multiple flow control groups have been created, each group will be executed in series.
Arguments
- Optional. options - Options for execution
- debug - Boolean. Logs out to the console information about execution for debugging.
- callback(err, result) - A callback that is invoked after all of the methods have been executed, or an error occurrs. If no error occurrs, result will be an object containing arrays of values from each function callback.
Example
// assuming an object exists called myObj
$f(myObj).series()
.doSomething(/* args */)
.doSomething(/* args */)
.doSomethingElse(/* args */)
.parallel()
.doSomethingMore(/* args */)
.go(function(err, result) {
if (err) { /* error */ } else {
/*
result :-
{
"doSomething" : [
{ /* return value from first doSomething */ }
{ /* return value from second doSomething */ }
],
"doSomethingElse" : [{ /* return value from doSomethingElse */ }],
"doSomethingMore" : [{ /* return value from doSomethingMore */ }]
}
*/
}
});
### Context Methods
The fluid context will wrap all function properties of an object.
NOTE: Fluid.js currently only supports methods that take a callback as the last argument:-
function(options, callback) -> callback(err, result)
function(arg1, arg2, ..., callback) -> callback(err, result)
etc...
Example
var myCalculator = {
addTen : function(val, callback) {
callback(null, val + 10 );
},
multiplyByTen : function(val, callback) {
callback(null, val * 10);
}
};
$f(myCalculator)
.addTen(1)
.addTen(2)
.multiplyByTen(2)
.go(function(err, result) {
/*
result :-
{
"addTen" : [11, 12],
"multiplyByTen" : [20]
}
*/
});
You can even use the result of previous callbacks in the arguments to other functions. See late bound arguments.
$f(myCalculator)
.addTen(1)
.multiplyByTen($f("this.addTen[0]"))
.go(function(err, result) {
/*
result :-
{
"addTen" : [11],
"multiplyByTen" : [110]
}
*/
});
### Late Bound Arguments - fluid(expression)
Late bound arguments are useful when you need the result of a previous function as an argument to another.
Arguments
- expression - String. A javascript expression to be evaluated when the function is called. 'this' is the current result so far, and will contain return values of all previously executed callbacks.
Example
$f(myCalculator)
.addTen(1)
.multiplyByTen($f("this.addTen[0]"))
.go(function(err, result) {
/*
result :-
{
"addTen" : [11],
"multiplyByTen" : [110]
}
*/
});
Note, Fluid treats all string passed to it as late bound argument expressions.
Copyright(c) 2012 Pete Clark
MIT license
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The above copyright notice and this permission notice shall be included in ALL copies or substantial portions of the Software.
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