Docs Help

Terms, Icons, and Labels

Many classes have shortcut names used when creating (instantiating) a class with a configuration object. The shortcut name is referred to as an alias (or xtype if the class extends Ext.Component). The alias/xtype is listed next to the class name of applicable classes for quick reference.

Access Levels

Framework classes or their members may be specified as private or protected. Else, the class / member is public. Public, protected, and private are access descriptors used to convey how and when the class or class member should be used.

Member Types

Member Syntax

Below is an example class member that we can disect to show the syntax of a class member (the lookupComponent method as viewed from the Ext.button.Button class in this case).

lookupComponent ( item ) : Ext.Component
protected

Called when a raw config object is added to this container either during initialization of the items config, or when new items are added), or {@link #insert inserted.

This method converts the passed object into an instanced child component.

This may be overridden in subclasses when special processing needs to be applied to child creation.

Parameters

item :  Object

The config object being added.

Returns
Ext.Component

The component to be added.

Let's look at each part of the member row:

Member Flags

The API documentation uses a number of flags to further commnicate the class member's function and intent. The label may be represented by a text label, an abbreviation, or an icon.

Class Icons

- Indicates a framework class

- A singleton framework class. *See the singleton flag for more information

- A component-type framework class (any class within the Ext JS framework that extends Ext.Component)

- Indicates that the class, member, or guide is new in the currently viewed version

Member Icons

- Indicates a class member of type config

- Indicates a class member of type property

- Indicates a class member of type method

- Indicates a class member of type event

- Indicates a class member of type theme variable

- Indicates a class member of type theme mixin

- Indicates that the class, member, or guide is new in the currently viewed version

Class Member Quick-Nav Menu

Just below the class name on an API doc page is a row of buttons corresponding to the types of members owned by the current class. Each button shows a count of members by type (this count is updated as filters are applied). Clicking the button will navigate you to that member section. Hovering over the member-type button will reveal a popup menu of all members of that type for quick navigation.

Getter and Setter Methods

Getting and setter methods that correlate to a class config option will show up in the methods section as well as in the configs section of both the API doc and the member-type menus just beneath the config they work with. The getter and setter method documentation will be found in the config row for easy reference.

History Bar

Your page history is kept in localstorage and displayed (using the available real estate) just below the top title bar. By default, the only search results shown are the pages matching the product / version you're currently viewing. You can expand what is displayed by clicking on the button on the right-hand side of the history bar and choosing the "All" radio option. This will show all recent pages in the history bar for all products / versions.

Within the history config menu you will also see a listing of your recent page visits. The results are filtered by the "Current Product / Version" and "All" radio options. Clicking on the button will clear the history bar as well as the history kept in local storage.

If "All" is selected in the history config menu the checkbox option for "Show product details in the history bar" will be enabled. When checked, the product/version for each historic page will show alongside the page name in the history bar. Hovering the cursor over the page names in the history bar will also show the product/version as a tooltip.

Search and Filters

Both API docs and guides can be searched for using the search field at the top of the page.

On API doc pages there is also a filter input field that filters the member rows using the filter string. In addition to filtering by string you can filter the class members by access level, inheritance, and read only. This is done using the checkboxes at the top of the page.

The checkbox at the bottom of the API class navigation tree filters the class list to include or exclude private classes.

Clicking on an empty search field will show your last 10 searches for quick navigation.

API Doc Class Metadata

Each API doc page (with the exception of Javascript primitives pages) has a menu view of metadata relating to that class. This metadata view will have one or more of the following:

Expanding and Collapsing Examples and Class Members

Runnable examples (Fiddles) are expanded on a page by default. You can collapse and expand example code blocks individually using the arrow on the top-left of the code block. You can also toggle the collapse state of all examples using the toggle button on the top-right of the page. The toggle-all state will be remembered between page loads.

Class members are collapsed on a page by default. You can expand and collapse members using the arrow icon on the left of the member row or globally using the expand / collapse all toggle button top-right.

Desktop -vs- Mobile View

Viewing the docs on narrower screens or browsers will result in a view optimized for a smaller form factor. The primary differences between the desktop and "mobile" view are:

Viewing the Class Source

The class source can be viewed by clicking on the class name at the top of an API doc page. The source for class members can be viewed by clicking on the "view source" link on the right-hand side of the member row.

Ext JS 6.2.1 - Classic Toolkit


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Hierarchy

Function

Summary

Every function in JavaScript is actually a Function object.

Function objects created with the Function constructor are parsed when the function is created. This is less efficient than declaring a function and calling it within your code, because functions declared with the function statement are parsed with the rest of the code.

All arguments passed to the function are treated as the names of the identifiers of the parameters in the function to be created, in the order in which they are passed.

Invoking the Function constructor as a function (without using the new operator) has the same effect as invoking it as a constructor.

Specifying arguments with the Function constructor

The following code creates a Function object that takes two arguments.

// Example can be run directly in your JavaScript console

// Create a function that takes two arguments and returns the sum of those
arguments
var adder = new Function("a", "b", "return a + b");

// Call the function
adder(2, 6);
// > 8

The arguments "a" and "b" are formal argument names that are used in the function body, "return a + b".

Documentation for this class comes from [MDN](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function) and is available under [Creative Commons: Attribution-Sharealike license](http://creativecommons.org/licenses/by-sa/2.0/).
No members found using the current filters

properties

Instance Properties

length : Number

Specifies the number of arguments expected by the function.

methods

Instance Methods

apply ( thisArg, argsArray ) : Object

Applies the method of another object in the context of a different object (the calling object); arguments can be passed as an Array object.

You can assign a different this object when calling an existing function. this refers to the current object, the calling object. With apply, you can write a method once and then inherit it in another object, without having to rewrite the method for the new object.

apply is very similar to call, except for the type of arguments it supports. You can use an arguments array instead of a named set of parameters. With apply, you can use an array literal, for example, fun.apply(this, ['eat', 'bananas']), or an Array object, for example, fun.apply(this, new Array('eat', 'bananas')).

You can also use arguments for the argsArray parameter. arguments is a local variable of a function. It can be used for all unspecified arguments of the called object. Thus, you do not have to know the arguments of the called object when you use the apply method. You can use arguments to pass all the arguments to the called object. The called object is then responsible for handling the arguments.

Since ECMAScript 5th Edition you can also use any kind of object which is array like, so in practice this means it's going to have a property length and integer properties in the range [0...length). As an example you can now use a NodeList or a own custom object like {'length': 2, '0': 'eat', '1': 'bananas'}.

You can use apply to chain constructors for an object, similar to Java. In the following example, the constructor for the Product object is defined with two parameters, name and value. Two other functions Food and Toy invoke Product passing this and arguments. Product initializes the properties name and price, both specialized functions define the category. In this example, the arguments object is fully passed to the product constructor and corresponds to the two defined parameters.

function Product(name, price) {
    this.name = name;
    this.price = price;

    if (price < 0)
        throw RangeError('Cannot create product "' + name + '" with a negative price');
    return this;
}

function Food(name, price) {
    Product.apply(this, arguments);
    this.category = 'food';
}
Food.prototype = new Product();

function Toy(name, price) {
    Product.apply(this, arguments);
    this.category = 'toy';
}
Toy.prototype = new Product();

var cheese = new Food('feta', 5);
var fun = new Toy('robot', 40);

Clever usage of apply allows you to use built-ins functions for some tasks that otherwise probably would have been written by looping over the array values. As an example here we are going to use Math.max/Math.min to find out the maximum/minimum value in an array.

//min/max number in an array
var numbers = [5, 6, 2, 3, 7];

//using Math.min/Math.max apply
var max = Math.max.apply(null, numbers); // This about equal to Math.max(numbers[0], ...) or
// Math.max(5, 6, ..)
var min = Math.min.apply(null, numbers);

//vs. simple loop based algorithm
max = -Infinity, min = +Infinity;

for (var i = 0; i < numbers.length; i++) {
if (numbers[i] > max)
    max = numbers[i];
if (numbers[i] < min)
    min = numbers[i];
}

But beware: in using apply this way, you run the risk of exceeding the JavaScript engine's argument length limit. The consequences of applying a function with too many arguments (think more than tens of thousands of arguments) vary across engines, because the limit (indeed even the nature of any excessively-large-stack behavior) is unspecified. Some engines will throw an exception. More perniciously, others will arbitrarily limit the number of arguments actually passed to the applied function. (To illustrate this latter case: if such an engine had a limit of four arguments [actual limits are of course significantly higher], it would be as if the arguments 5, 6, 2, 3 had been passed to apply in the examples above, rather than the full array.) If your value array might grow into the tens of thousands, use a hybrid strategy: apply your function to chunks of the array at a time:

function minOfArray(arr)
{
    var min = Infinity;
    var QUANTUM = 32768;
    for (var i = 0, len = arr.length; i < len; i += QUANTUM)
    {
        var submin = Math.min.apply(null, numbers.slice(i, Math.min(i + QUANTUM, len)));
        min = Math.min(submin, min);
    }
return min;
}

var min = minOfArray([5, 6, 2, 3, 7]);

Parameters

thisArg :  Object

The value of this provided for the call to fun. Note that this may not be the actual value seen by the method: if the method is a function in non-strict mode code, null and undefined will be replaced with the global object, and primitive values will be boxed.

argsArray :  Array

An array like object, specifying the arguments with which fun should be called, or null or undefined if no arguments should be provided to the function.

Returns

:Object
Returns what the function returns.

bind ( thisArg, [args] ) : Function

Creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function was called.

The bind() function creates a new function (a bound function) with the same function body (internal Call attribute in ECMAScript 5 terms) as the function it is being called on (the bound function's target function) with the this value bound to the first argument of bind(), which cannot be overridden. bind() also accepts leading default arguments to provide to the target function when the bound function is called. A bound function may also be constructed using the new operator: doing so acts as though the target function had instead been constructed. The provided this value is ignored, while prepended arguments are provided to the emulated function.

Creating a bound function

The simplest use of bind() is to make a function that, no matter how it is called, is called with a particular this value. A common mistake for new JavaScript programmers is to extract a method from an object, then to later call that function and expect it to use the original object as its this (e.g. by using that method in callback-based code). Without special care, however, the original object is usually lost. Creating a bound function from the function, using the original object, neatly solves this problem:

var x = 9;
var module = {
  x: 81,
  getX: function() { return this.x; }
};

module.getX(); // 81

var getX = module.getX;
getX(); // 9, because in this case, "this" refers to the global object

// create a new function with 'this' bound to module
var boundGetX = getX.bind(module);
boundGetX(); // 81

Partial functions

The next simplest use of bind() is to make a function with pre-specified initial arguments. These arguments (if any) follow the provided this value and are then inserted at the start of the arguments passed to the target function, followed by the arguments passed to the bound function, whenever the bound function is called.

function list() {
  return Array.prototype.slice.call(arguments);
}

var list1 = list(1, 2, 3); // [1, 2, 3]

//  Create a function with a preset leading argument
var leadingZeroList = list.bind(undefined, 37);

var list2 = leadingZeroList(); // [37]
var list3 = leadingZeroList(1, 2, 3); // [37, 1, 2, 3]

NOTE: This method is part of the ECMAScript 5 standard.

Parameters

thisArg :  Object

The value to be passed as the `this` parameter to the target function when the bound function is called. The value is ignored if the bound function is constructed using the new operator.

args :  Mixed... (optional)

Arguments to prepend to arguments provided to the bound function when invoking the target function.

Returns

:Function
The bound function.

call ( thisArg, args ) : Object

Calls (executes) a method of another object in the context of a different object (the calling object); arguments can be passed as they are.

You can assign a different this object when calling an existing function. this refers to the current object, the calling object.

With call, you can write a method once and then inherit it in another object, without having to rewrite the method for the new object.

You can use call to chain constructors for an object, similar to Java. In the following example, the constructor for the product object is defined with two parameters, name and value. Another object, prod_dept, initializes its unique variable (dept) and calls the constructor for product in its constructor to initialize the other variables.

function Product(name, price) {
    this.name = name;
    this.price = price;

    if (price < 0)
        throw RangeError('Cannot create product "' + name + '" with a negative price');
    return this;
}

function Food(name, price) {
    Product.call(this, name, price);
    this.category = 'food';
}
Food.prototype = new Product();

function Toy(name, price) {
    Product.call(this, name, price);
    this.category = 'toy';
}
Toy.prototype = new Product();

var cheese = new Food('feta', 5);
var fun = new Toy('robot', 40);

In this purely constructed example, we create anonymous function and use call to invoke it on every object in an array. The main purpose of the anonymous function here is to add a print function to every object, which is able to print the right index of the object in the array. Passing the object as this value was not strictly necessary, but is done for explanatory purpose.

var animals = [
{species: 'Lion', name: 'King'},
{species: 'Whale', name: 'Fail'}
];

for (var i = 0; i < animals.length; i++) {
    (function (i) {
    this.print = function () {
        console.log('#' + i  + ' ' + this.species + ': ' + this.name);
    }
}).call(animals[i], i);
}

Parameters

thisArg :  Object

The value of this provided for the call to `fun`.Note that this may not be the actual value seen by the method: if the method is a function in non-strict mode code, `null` and `undefined` will be replaced with the global object, and primitive values will be boxed.

args :  Object...

Arguments for the object.

Returns

:Object
Returns what the function returns.

constructor ( args, functionBody )

Creates new Function object.

Parameters

args :  String...

Names to be used by the function as formal argument names. Each must be a string that corresponds to a valid JavaScript identifier or a list of such strings separated with a comma; for example "`x`", "`theValue`", or "`a,b`".

functionBody :  String

A string containing the JavaScript statements comprising the function definition.

toString String

Returns a string representing the source code of the function. Overrides the Object.toString method.

The Function object overrides the toString method of the Object object; it does not inherit Object.toString. For Function objects, the toString method returns a string representation of the object.

JavaScript calls the toString method automatically when a Function is to be represented as a text value or when a Function is referred to in a string concatenation.

For Function objects, the built-in toString method decompiles the function back into the JavaScript source that defines the function. This string includes the function keyword, the argument list, curly braces, and function body.

Returns

:String
The function as a string.

Ext JS 6.2.1 - Classic Toolkit