async-if-else

This module adds if else conditional capabilities to async module.

Ever came across code like this on your async.waterfall flow?

``javascript
var async = require('async');

async.waterfall([
async.constant({email: 'thiago@email.com', dogs: 2, money: 0, fun: 100 }),
updateUserEmailOrGetLegacy,
sendEmail
], handler);

function updateUserEmailOrGetLegacy(user, cb) {
emailExists(user.email, function (err, value) {
if (err)
callback(err)
else {
if (user.email)
updateAccount(user, cb);
else
importFromLegacyByEmail(user, cb)
}
})
}
`

Using async-if-else you can have a conditional waterfall without the need of a wrapper function.
And the code is so much more readable, don't you agree?

`javascript
var async = require('async-if-else')(require('async'));

function emailExists(user, callback) {
user.find(user.email, function(err, dbUser){
if (err)
return callback(error);

if(!dbUser)
return callback(null, false); // does not exist, predicate will be false

callback(null, true);
});
}

function updateAccount(user, callback) {
user.update( ..., callback);
}

function importFromLegacyByEmail(user, callback) {
remoteClient.get(user, callback);
}

async.waterfall([
async.constant({email: 'thiago@email.com', dogs: 2, money: 0, fun: 100 }),
async.if(emailExists, updateAccount).else(importFromLegacyByEmail),
sendEmail
], handler);
`

You can also omit the else and the function is only executed if the predicate is true.

`javascript
var async = require('async-if-else')(require('async'));

async.waterfall([
async.constant({email: 'thiago@email.com', dogs: 2, money: 0, fun: 100 }),
async.if(emailExists, auditLogging),
publishToQueue
], handler);
`

if you don't want to change the async object, you can always do something like that

`javascript
var async = require('async');
var conditional = require('async-if-else')({});

async.waterfall([
async.constant({email: 'thiago@email.com', dogs: 2, money: 0, fun: 100 }),
conditional.if(emailExists, auditLogging),
publishToQueue
], handler);

`

API

* initializer
* if
* else
* ifNot
* unless


`javascript
async.if()
async.if().else()
async.ifNot()
async.ifNot().else()
async.unless()
async.unless().else()
`




$3

To get start with async-if-else you need to provide an object.

`javascript
var conditionals = require('async-if-else')({});
`

`javascript
var async = require('async-if-else')(require('async'));
`




$3

if function receives the predicate and the expression.

async.if(predicateFn, expressionFn)

* predicateFn must validate the argument received from waterfall chain

`javascript
function predicateFn(arg1 [, arg2 ...], callback) {}
`

callback signature is callback(error, truthyValue|falsyValue);
if you pass an error on first parameter the async.waterfall will skip below steps and goes directly to async.waterfall's callback function.

* expressionFn will execute when predicate is thruthy.

`javascript
function expressionFn(arg1 [,arg2...], asyncWaterfallCallback)
`




$3

else receives only an elseExpressionFn

async.if(predicateFn, expressionFn).else(elseExpressionFn);

* elseExpressionFn is executed when the if predicate is falsy or ifNot predicate is truthy.

`javascript
function elseExpressionFn(arg1 [,arg2...], asyncWaterfallCallback)
`




$3

ifNot works as the opposite of If
receives exactly the same arguments

async.ifNot(predicateFn, expressionFn)

you could use with else as well

async.ifNot(predicateFn, expressionFn).else(elseExpressionFn)




$3


just an alias to ifNot`.

#### Hey, did you found an issue?

The best way to get in touch is using the GitHub issues section.
If you can't find someone with the problem you are facing open a new issue and let me know.
If you manage to find a solution for your problem, you can submit a new PR :)

Let's make the world a better place by helping others.

License

MIT