jQuery.my

Below API description is not complete, see jquerymy.com for more detailed API, examples and list of compatible controls.

• Get/set data
• Validation
• Dependencies
• Conditional formatting
• Form init
• Nested forms
• Styling forms

jquerymy is a plugin for complex reactive two-way data binding between DOM and nested JS state objects.

jquerymy recognizes standard HTML controls as well as composite controls rendered by jQuery Mobile, nearly all jQuery UI widgets, Redactor, Ace, CodeMirror, Select2 and others.

jquerymy provides comprehensive validation, conditional formatting and dependencies resolution. Apps can be nested – each $.my instance can be used as control in a parent form, if any.

jquerymy also incorporates simple template engine and modal dialog mechanics.

See cloudwall.me as an example of web-app platform built on top of $.my. Also good example of a very large jquerymy app is Photon, an unofficial administrative panel for CouchDB.

Setup

jQuery.my requires jQuery 2.0+ and SugarJS 1.3.9–1.4.1.

<script src="/js/sugar.min.js"></script>
<script src="/js/jquery.min.js"></script>
<script src="/js/jquerymy.min.js"></script>

$.my can can be installed from npm – npm install jquerymy, same for bower.

Quick start

var person={};
var manifest = {
	"data": { name:"", metrics:{ age:"" }},
	"init": function ($node, formRuntimeObj) {
		$node.html(
			'<div><input id="name" type="text" /></div>' +
			'<div><input id="age" type="number" /></div>'
		);
	},
	"ui":{
		"#name": { bind: "name" },
		"#age" : { bind: "metrics.age" }
	}
};
// Init $.my
$("#form").my(manifest, person);
```	
Now form inputs are filled with init values and any interaction with controls immediately mutates `person` object. Dot notation of deep-level bindings is just syntax sugar. It also can be used with arrays in style like `someArray.1`.

First param passed to $.my is denoted below as __manifest__.

Retrieving and updating data
-----

__To get__ form data just read value of the `person` variable or read `$("#form").my("data")`. Second way is good if $.my was initialized without any init value passed. 

__To put__ new data into already initialized instance of $.my call `$("#form").my("data", {name: "Mike"})`. Note you can update data partially. Form is redrawn and revalidated after applying new data .

More complex data bind
-----

The `.bind` field can be defined as a bi-directional function. It receives entire data object and new value as params. 
If `null` is passed function must only return value for DOM control, otherwise function must put value into 
data object and then return value for DOM.

So `bind` function implements both getter and setter – depending on value passed.

```js
$("#form").my({
	ui:{
		"#name": "name",
		"#age" : {
			bind: function (data, value, $control) {
				if (value != null) data.metrics.age = value; 
				return data.metrics.age = 
					(data.metrics.age + "").replace(/\D/g,"");
			}
		}
	}
}, person);

Note bind function in example won't allow to input anything than number. Pressing non-num key will do nothing with input, non-num chars are stripped immediately.

Third param $control is jQuery reference to the control being processed, it can be useful for navigating over form. Calling $control.my("find", "#name") returns #name control for example.

Validation

There are several ways to validate data received from control. Validator can be a regexp or a function. Functions unlike regexps can return custom error messages depending on value being checked. Check is performed just before executing .bind.

If value is incorrect .my-error class is applied to the closest DOM container of the control, otherwise this style rule is removed.

If control is not interactive – we bind some data with <div> element for example – .my-error class is applied to the element itself, not container.

RegExp validation

$("#form").my({
	ui:{
		"#name": { 
			bind: "name", 
			check:/^[a-z]{10}$/i,
			error:"10 latin chars" // Optional
		},
		"#age":  { bind: "metrics.age" }
	}
});

If user puts something other than 10-letter combination into #name input, class attribute of the parent <div> is set to .my-error.

Validating with function

Validator function receives same params as .bind but executed before bind. Validator must return error message string – or empty string if value is ok.

Unlike .bind validator is never called with value equal to null, it always receives real value.

$("#form").my({
	data:{/*...*/},
	init: function ($node){/*...*/},
	ui:{
		"#name": { 			
			"bind": "name", 
			"check": function (data, value, $control) {
				if (value.length > 20) return "Too long name"; 
				if (!/^[a-z]+$/.test(value)) return "Only letters allowed"; 
				return "";
			}			
		},
		"#age": "age"
	}
});

Messages returned by validator are put into DOM element with class .my-error-tip, which must be located inside the control’s container. So to make messages visible you must explicitly add this element into html. If no such element found error message will be added as title attribute to the control itself. If the control has own title, its value is stashed until error corrected.

<div>
	<input id="name" type="text" />
	<span class="my-error-tip"></span>
</div>
```	
#### Checking entire form has no errors
`$("#form").my("errors")` returns an object, which keys are invalid fields, and values are error messages. If all fields are ok, `{}` is returned. If form has children forms, their errors are mapped to appropriate branch.

To spot whether entire data is valid call `$("#form").my("valid")`, which returns `true` is everything is ok.
	
Dependencies
-----

Let it be a form that calculates product of two values. We need to recalculate product each time any of factors changes.
```js
$("#form").my({
	data:{ num1:"10", num2:"1.5" },
	init: function ($node){/*...*/},
	ui:{
		"#factor1": "num1", 
		"#factor2": "num2",
		"#product": {
			bind: function (data) {
				return data.num1 * data.num2;
			},
			watch: "#factor1,#factor2" //shorthand for ["#factor1", "#factor2"]
		}
	}
});

Product is not mapped to data – .bind function does not save anything. It only returns value to put in #product DOM element. Every time #factor1 or #factor2 receive input #product is recalculated.

There is another syntax to define dependencies.

$("#form").my({
	ui:{
		"#factor1": {
			bind: "num1", 
			recalc: "#product"
		},
		"#factor2": "num2",
		"#product": {
			bind: function (data) {return data.num1 * data.num2},
			watch: "#factor2"
		}
	}
});

It behaves the same way. Note that .recalc is processed prior to .watch. So if a field depends on some other fields via both .recalc and .watch attributes, recalcs go first.

Loop dependencies are resolved correctly.

Conditional formatting and disabling

$.my can apply different classes depending on data object state.

$("#form").my({
	ui:{
		"#name": { 			
			bind: "name", 
			recalc: "#age",
			css: {
				"orange":/^.{10}$/
			}	
		},
		"#age": {
			bind: "age",
			css:{
				":disabled": function (data, value) {
					return data.name.length == 0;
				}
			}
		}
	}
});

Here if #name is exactly 10 chars, its container will receive class orange. If value doesn't match regexp then class orange is removed.

Input #age depends on value of #name field and is disabled if data.name is empty.

Conditional formatting over appropriate field is applied after .check and .bind.

Init functions

Preparing form during initialization

$("#form").my({
	data: { range: [30, 70] },
	init: function ($node) {
		$node.html('<input id="range" />')
	},
	ui:{
		"#range": { 	
			init: function ($control) {
				$control.slider(range: true, min: 0, max: 100);
			},	
			bind: "range"
		}
	}
});

Here we apply jQuery.UI Slider plugin over #range control. Data attribute range will receive array of two values – slider start and stop. On start control will be set to 30–70 range.

Certainly HTML carcass itself can be generated using init function, placed as child of manifest's root – as in above example.

Async init

To become async .init function must return promise of any sort (so-called ‘then-able’). Initialization sequence continues when the promise is resolved. If app promise is rejected, entire sequence also fails.

$("#form")
.my({
	data: { name:"" },
	init: function ($node, runtime) {
		var promise = $.ajax({
			url:"http://some.url"
		}).then(function (res) {
			// We received response, gen form HTML
			$node.html('<input id="name" type="text"/>')
			// Assume res is string, mount default data
			runtime.data.name = res;
		});
		
		return promise;
	},
	ui:{"#name": "name"}
})
.then(function (data){
	// Do something when form init finished 
})
.fail(function(errMessage) {
	// Do something if init failed
});

jQuery AJAX implementation returns promise, so we may return $.ajax result directly. When data is received promise is resolved and initialization continues. When it is finished, promise returned by $.my is resolved with form’s .data.

Nested and repeated forms

Each DOM node which was instantiated with $.my can act as a single control for some parent $.my form. DOM node #child is instantiated with own manifest in example.

$("#form")
.my({
	data: { name:"" , child:{}},
	init: function ($node, runtime) {
		//Draw HTML
	},
	ui:{
		"#name": "name",
		"#child" :{
			bind:"child", 
			check:true,		//ensures child’s errors invalidate parent
			manifest:{
				data:{/* child’s data struct */},
				init:{/* child’s init, can be async */},
				ui:{ /* child’s ui */}
			}
		}
	}
})

To build list of nested forms just bind it with array. Below example builds list of similar array elements.

$("#form")
.my({
	data: { name:"" , child:[ /* array of elts */]},
	init: function ($node, runtime) {
		//Draw HTML
	},
	ui:{
		"#name": "name",
		"#child" :{
			bind:"child", 
			check:true,
			list:'<div class="someClass"></div>', 	//optional
			init: function ($list) {				//optional
				// Makes list items sortable by drag 
				// and drop, jQuery UI plugin required
				$list.sortable();
			},
			manifest:{
				data:{/* child’s data struct */},
				init:{/* child’s init, can be async */},
				ui:{ /* child’s ui */}
			},
			
		}
	}
})

Tuning behavior

Events

$.my understands many types of controls and automatically selects appropriate event handler(s) to provide real-time binding. It’s a kind of device driver for different plugins and conventional HTML inputs or noninteractive elements.

But sometimes you need no realtime response – in case of buttons or links for example. Bind function must be executed only when button is really clicked, not while initializing.

$("#form").my({
	ui:{
		"#button": { 			
			bind: function (data, value) {
				if (value != null) {
					//do something
				}
			}, 
			events: "click,dblclick"	
		}
	}
});

The events attribute here defines that bind executed after click or doubleclick events on #button element. Note .bind returns undefined here – this syntax allows us to keep control's content intact.

Delays

There are several cases bind function must have kind of an anti-jitter. If control is jQuery.UI Slider or conventional HTML5 <input type="range"> it’s reasonable to exec .bind when slider stops. Complex bind function executed every pixel slider moves can be real CPU and RAM hog.

$("#form").my({
	ui:{
		"#slider": { 			
			bind: function (data, val) { /* do somth*/ }, 
			delay: 150	
		}
	}
});

In this example .bind starts only after last event within 150ms. If change events are raised more often then one in 150ms, they are supressed. See live demo – its much more clear than description.

Reusable code snippets

Some functions or fields inside manifest can contain code with matching fragments. It can be same regexps for different fields, or some dictionaries used here and there etc. They can be stored at manifest's root and acessed from ui section members by reference.

$("#form").my({
	NumCheck:/^\d+$/,
	ForbiddenPasswords:["123","qwerty"],
	ui:{
		"#num": { 	
			bind: "num",
			check: "NumCheck"
		},
		"#pwd":{
			bind:"password",
			check: function (data, value) {
				var pwdList = this.ForbiddenPasswords;
				if (pwdList.indexOf(value) == -1) return "Too simple password!";
				return "";
			}
		}
	},
	SomeFunction: function () { // this points to runtime manifest }
});

Not only checks but every function defined in .ui section receives this pointing to runtime manifest. Functions located on the first level of manifest (SomeFunction in example above) also receive this pointing to runtime.

Manifest delivery

There is buil-in method to convert manifest with functions and regexps into conventional JSON. It's useful for on-demand manifest delivery using ajax calls. $.my.tojson(manifest) returns correct JSON-encoded string with all functions and regexps converted to strings.

This approach is used in CouchDB to store internal functions as JSON docs. It's quite simple and straightforward.

$.my.tojson({
	a:function(){}, 
	b:/./
})  
>> '{"a":"function (){}", "b":"new RegExp(/./)"}'
```	
Method `$.my.fromjson(someJSON)` unwinds encoded functions and regexps into full-featured code.

There is no need to decipher encoded manifests before passing them to $.my – they are unwinded automatically.

Styling forms
-----

Manifest can contain `style` property that defines hierarchy of css rules for form instance. Some rules can be static and other calculated according to form’s init data.
```javascript
{
	id:"ManifestId",
	data:{...},
	init function(){...},
	ui:{...},
	style:{
		" .red": "color:#c02",
		" .item":{
			" .name": "font-size:110%",
			" .user": function ($form, form) {
				if ($form.width()<500) return "display:none";
				return "font-size:80%";
			}
		},
		" h2,h3":{
			"": 		 "font-weight:bold"
			".light": 	 "font-weight:normal",
			">img.icon": "width:24px;"
		}
	}
}

Syntax is more or less straightforward. Note spaces before most rules. Above example will be rendered in two <style> sections.

<style id="my-manifest-abc123def">
	.my-manifest-abc123def .red:{color:#c02}
	.my-manifest-abc123def .item .name {font-size:110%}
	.my-manifest-abc123def .h2 {font-weight:bold}
	...
</style>
<style id="my-form-098fea432">
	.my-form-098fea432 .item .user:{display:none}
</style>

First is static and generated from string definitions. If manifest – like in example – has id, this <style> section generated only once regardless of number of manifest instances running. When last instance dies, this section will be removed.

Second <style> section is unique for each manifest’s instance and is generated from rules, defined with functions. They can tune rules according to form size or init data. In example if container is too narrow, no .user is shown.

Style section is evaluated before init to ensure init see real geometry of objects it puts to the page.

Settings

Below parameters of $.my instance can be tuned for an entire form:

var manifest = {
	params:{
		delay: 0,		//global anti-jitter delay, can be overriden
		depth: 2,		//depth of chained/looped recalc resolution
		errorTip: ".my-error-tip",		//jQuery selector for error msg
		errorCss: "my-error"			//class to mark invalid controls
	},
	data: {...},
	init: function ($form) {...},
	ui:{...}
};

Full set of settings is quite long, they are listed and explained at jquerymy.com/api.html

Compatibility

Works fine on IE9+ and other browsers. IE8 is also supported, but apps require thorough testing and optimizations to avoid lags.