dta

Dynamically typed arguments

Or in short "DTA". Is a library to map arguments by type or prototype.

How to install

You are able to use this module in Node.js and in your browser as global-function or as amd-module. You can fetch this module using npm or Bower.

Node

You can get the package with:

npm install dta

After that you are able to load this module the common node.js way:

var dta = require('dta');

Fetch with Bower

You can get the package with:

bower install dta

Fetch with git

git clone https://github.com/atd-schubert/dta.git

Download with wget

wget https://github.com/atd-schubert/dta/archive/master.zip

Require in browsers

If you are not using AMD, you have to add a script-tag with the dta.js as src attribute.

If you are using AMD, you have to put the dta.js file into your scripts folder, or edit your shim-config accordingly and require this module with require(['dta'], function (dta) { /* now you have the dta-function available in this scope... */ }).

How to use DTA

The main idea behind DTA is to pass the arguments variable of any function to DTA and get an object of arguments by type, so you are not forced to give your function parameters an order.

Example request an URL

Adopted you have a function where you want to request an url, it is not necessary if you want to do this with an ajax call, or with a function called request in node, you can do this the following way:

// you have already loaded DTA with one of the above described methods.
var getContent;

getContent = function getContent() {
    var params, opts;

    opts = {};

    params = dta({
        string: 'url',
        number: 'timeout',
        function: 'callback'
    }, arguments);

    if (params.timeout) {
       opts.timeout = params.timeout;
    }

    if (!params.url) {
       throw new Error('You have to specify an url');
    }
    if (!params.callback) {
       throw new Error('You have to specify a callback');
    }

    request(params.url, opts, params.callback);

};

Now the order of your parameters in getContent is not necessary any more.

But DTA is also able to get mandatory parameters:

// you have already loaded DTA with one of the above described methods.
var getContent;

getContent = function getContent() {
    var params, opts;

    opts = {};

    params = dta({
        mandatory: ['url', 'callback'],
        string: 'url',
        number: 'timeout',
        function: 'callback'
    }, arguments);

    if (params.timeout) {
       opts.timeout = params.timeout;
    }

    request(params.url, opts, params.callback);
};

Multiple parameters of the same type

DTA can handle multiple arguments of the same type:

// you have already loaded DTA with one of the above described methods.
var sayHello;

sayHello = function sayHello() {
    var params;

    params = dta({
        mandatory: 'firstName',
        string: ['firstName', 'surname']
    }, arguments);

    if (!params.surname) {
        return 'Hi ' + params.firstName;
    }
    return 'Hello ' + params.firstName + params.surname;
};

Lists of a parameter

If you have unspecific number of parameters of a type you are able to handle it this way:

// you have already loaded DTA with one of the above described methods.
var factorize;

factorize = function factorize() {
    var params, i, result;

    params = dta({
        mandatory: 'factor',
        number: '[factor]'
    }, arguments);

    result = params.factor[0];

    for (i = 1; i < params.factor.length; i += 1) {
        result *= params.factor[i];
    }

    return result;
};

List of supported basic types

• boolean
• number
• string
• function
• object
• array
• error
• regExp
• argument

Make your own types

DTA is also able to handle your own types. You have to define your prototypes in an object to give them a name and map them the default way:

// you have already loaded DTA with one of the above described methods.
var anyFunction, myOwnClass;

myOwnClass = function () {
    // Your class logic
}

anyFunction = function anyFunction() {
    var params;

    params = dta({
            prototypes: {
                own: myOwnClass
            },
            own: 'own',
            // [...]
        }, arguments);

    // do something with params.own
};

anyFunction(new myOwnClass());

Does it has to be arguments?

No, you are also able to use DTA with normal arrays!

Pass a function instead of arrays or arguments

You can also use dta to create a function (with thanks to Andreas for this idea!)

// you have already loaded DTA with one of the above described methods.
var factorize;

factorize = dta({
    mandatory: 'factor',
    number: '[factor]'
}, function factorize(params) {
    var i, result;

    result = params.factor[0];

    for (i = 1; i < params.factor.length; i += 1) {
        result *= params.factor[i];
    }

    return result;
});

Use your preferred order of arguments in DTA

The order of the two arguments in DTA is not compulsory. If you want you can pass arguments first.

// you have already loaded DTA with one of the above described methods.
var factorize;

factorize = function factorize() {
    var params, i, result;

    params = dta(arguments, {
        mandatory: 'factor',
        number: '[factor]'
    });

    result = params.factor[0];

    for (i = 1; i < params.factor.length; i += 1) {
        result *= params.factor[i];
    }

    return result;
};