Class Skipper

A skipper is an object working with zk.Widget#rerender to rerender portion(s) of a widget (rather than the whole widget). It can improve the performance a lot if it can skip a lot of portions, such as a lot of child widgets.

The skipper decides what to skip (i.e., not to rerender), detach the skipped portion(s), and attach them back after rerendering. Thus, the skipped portion won't be rerendered, nor unbound/bound.

The skipper has to implement three methods, skipped, skip and restore. skipped is used to test whether a child widget shall be skipped. skip and restore works together to detach and attach the skipped portions from the DOM tree. Here is how zk.Widget#rerender uses these two methods: ```ts rerender: function (skipper) { var skipInfo; if (skipper) skipInfo = skipper.skip(this);

this.replaceHTML(this.node, null, skipper);

if (skipInfo) skipper.restore(this, skipInfo); }

<p>Since <a href="zk.Widget.html#rerender" class="tsd-kind-method">zk.Widget#rerender</a> will pass the returned value of <a href="zk.Skipper.html#skip" class="tsd-kind-method">skip</a> to <a href="zk.Skipper.html#restore" class="tsd-kind-method">restore</a>, the skipper doesn't need to store what are skipped. That means, it is possible to have one skipper to serve many widgets. <a href="zk.Skipper.html#nonCaptionSkipper" class="tsd-kind-property">nonCaptionSkipper</a> is a typical example.
<p>In additions to passing a skipper to <a href="zk.Widget.html#rerender" class="tsd-kind-method">zk.Widget#rerender</a>, the widget has to implement the mold method to handle the skipper:
```ts
function (skipper) {
    var html = '<fieldset' + this.domAttrs_() + '>',
        cap = this.caption;
    if (cap) html += cap.redraw();

    html += '<div id="' + this.uuid + '$cave"' + this._contentAttrs() + '>';
    if (!skipper)
    for (var w = this.firstChild; w; w = w.nextSibling)
        if (w != cap) html += w.redraw();
    return html + '</div></fieldset>';
}

See also ZK Client-side Reference: Property Rendering.

Hierarchy (view full)

Constructors

constructor

Properties

$oid $oid nonCaptionSkipper

Accessors

$class

Methods

$init $instanceof $super $supers afterInit get$Class proxy restore skip skipped isAssignableFrom isInstance

Constructors

constructor

  • new Skipper(..._rest): Skipper

  • Parameters

    • Rest ..._rest: any[]

    Returns Skipper

Properties

$oid

$oid: number = 0

The object ID. Each object has its own unique $oid. It is mainly used for debugging purpose.

Trick: you can test if a JavaScript object is a ZK object by examining this property, such as `if (o.$oid) alert('o is a ZK object');`

Notice: zk.Class extends from zk.Object (so a class also has $oid)

Static $oid

$oid: any

Static nonCaptionSkipper

nonCaptionSkipper: Skipper = ...

An instance of zk.Skipper that can be used to skip the rerendering of child widgets except the caption.

It assumes

  1. The child widget not to skip can be found by the caption data member.
  2. The DOM elements to skip are child elements of the DOM element whose ID is widgetUUID$cave, where widgetUUID is the UUID of the widget being rerendered.

In other words, it detaches (i.e., skipped) all DOM elements under widget.$n('cave'). ```ts setClosable: function (closable) { if (this._closable != closable) { this._closable = closable; if (this.node) this.rerender(zk.Skipper.nonCaptionSkipper); } } ```

Accessors

$class

  • get $class(): typeof ZKObject

  • The class that this object belongs to.

    Returns typeof ZKObject

Methods

$init

  • $init(props?): void

  • The constructor.

    Parameters

    • Optional props: Record<string, unknown> | (() => void)

    Returns void

    Default Value

    it does nothing so the subclass needs not to copy back
    (also harmless to call back).

    See

    afterInit

    Deprecated

    as of 10.0 released. Using ES6 constructor instead.

$instanceof

  • $instanceof(...klass): boolean

  • Determines if this object is an instance of the class represented by the specified Class parameter. Example:

    if (obj.$instanceof(zul.wgt.Label, zul.wgt.Image)) {
    }

    Parameters

    • Rest ...klass: any[]

      the Class object to be checked. Any number of arguments can be specified.

    Returns boolean

    true if this object is an instance of the class

$super

  • $super<M, F>(mtd, ...args): ReturnType<F>

  • Invokes a method defined in the superclass with any number of arguments. It is like Function's call() that takes any number of arguments.

    Example: ```ts multiply: function (n) { return this.$super('multiply', n + 2); } ```

    Type Parameters

    • M extends "$init" | "$supers" | "_$ais" | "_$supers" | "_$proxies" | "_$super" | "_importantEvts" | "afterCreated_" | "afterInit" | "$class" | "get$Class" | "$oid" | "$instanceof" | "$super" | "proxy" | "skipped" | "skip" | "restore"

    • F extends any

    Parameters

    • mtd: M

      the method name to invoke

    • Rest ...args: Parameters<F>

      any number of arguments

    Returns ReturnType<F>

    the object being returned by the method of the superclass.

    See

    zk.Object.$supers

  • $super<M, F>(klass, mtd, ...args): ReturnType<F>

  • Invokes a method defined in the superclass with any number of arguments. It is like Function's call() that takes any number of arguments.

    It is similar to ZKObject.$super, but this method works even if the superclass calls back the same member method. In short, it is tedious but safer.

    Example: ```ts foo.MyClass = zk.$extends(foo.MySuper, { multiply: function (n) { return this.$super(foo.MyClass, 'multiply', n + 2); } ```

    Notice that the class specified in the first argument is not the super class having the method. Rather, it is the class that invokes this method.

    Type Parameters

    • M extends "$init" | "$supers" | "_$ais" | "_$supers" | "_$proxies" | "_$super" | "_importantEvts" | "afterCreated_" | "afterInit" | "$class" | "get$Class" | "$oid" | "$instanceof" | "$super" | "proxy" | "skipped" | "skip" | "restore"

    • F extends any

    Parameters

    • klass: typeof ZKObject

      the class that invokes this method.

    • mtd: M

      the method name to invoke

    • Rest ...args: Parameters<F>

      any number of arguments

    Returns ReturnType<F>

    the object being returned by the method of the superclass.

    See

    zk.Object.$supers

    Since

    5.0.2

$supers

  • $supers<M, F>(name, args): ReturnType<F>

  • Invokes a method defined in the superclass with an array of arguments. It is like Function's apply() that takes an array of arguments.

    Example: ```ts multiply: function () { return this.$supers('multiply', arguments); } ```

    Type Parameters

    • M extends "$init" | "$supers" | "_$ais" | "_$supers" | "_$proxies" | "_$super" | "_importantEvts" | "afterCreated_" | "afterInit" | "$class" | "get$Class" | "$oid" | "$instanceof" | "$super" | "proxy" | "skipped" | "skip" | "restore"

    • F extends any

    Parameters

    • name: M

      the method name to invoke

    • args: Parameters<F>

      an array of arguments. In most case, you just pass arguments (the built-in variable).

    Returns ReturnType<F>

    the object being returned by the method of the superclass.

    See

    zk.Object.$super

  • $supers<M, F>(klass, name, args): ReturnType<F>

  • Invokes a method defined in the superclass with an array of arguments. It is like Function's apply() that takes an array of arguments.

    It is similar to zk.Object.$supers, but this method works even if the superclass calls back the same member method. In short, it is tedious but safer.

    Example: ```ts foo.MyClass = zk.$extends(foo.MySuper, { multiply: function () { return this.$supers(foo.MyClass, 'multiply', arguments); } ```

    Notice that the class specified in the first argument is not the super class having the method. Rather, it is the class that invokes this method.

    Type Parameters

    • M extends "$init" | "$supers" | "_$ais" | "_$supers" | "_$proxies" | "_$super" | "_importantEvts" | "afterCreated_" | "afterInit" | "$class" | "get$Class" | "$oid" | "$instanceof" | "$super" | "proxy" | "skipped" | "skip" | "restore"

    • F extends any

    Parameters

    • klass: typeof ZKObject

      the class that invokes this method.

    • name: M

      the method name to invoke

    • args: Parameters<F>

      an array of arguments. In most case, you just pass arguments (the built-in variable).

    Returns ReturnType<F>

    the object being returned by the method of the superclass.

    See

    zk.Object.$super

    Since

    5.0.2

afterInit

  • afterInit(func): void

  • Specifies a function that shall be called after the object is initialized, i.e., after zk.Object.$init is called. This method can be called only during the execution of zk.Object.$init.

    It is an advance feature that is used to allow a base class to do something that needs to wait for all deriving classes have been initialized.

    Invocation Sequence:

    • The most derived class's $init (subclass)
    • The based class's $init (if the derived class's $init invokes this.$supers('$init', arguments))
    • The first function, if any, be added with afterInit, then the second (in the same order that afterInit was called)...

    Parameters

    • func: CallableFunction

      the function to register for execution later

    Returns void

    See

    zk.Object.$init

    Deprecated

    as of 10.0 released. Using afterCreated_ instead.

get$Class

  • get$Class<T>(): T

  • Type Parameters

    Returns T

    the class of the subsclass which extends from zk.Class.

    Since

    10.0.0

proxy

  • proxy<A, R>(func): ((...args) => R)

  • Proxies a member function such that it can be called with this object in a context that this object is not available. It sounds a bit strange at beginning but useful when passing a member of an object that will be executed as a global function.

    Example: Let us say if you want a member function to be called periodically, you can do as follows. ```ts setInterval(wgt.proxy(wgt.doIt), 1000); //assume doIt is a member function of wgt ```

    With proxy, when doIt is called, this references to wgt. On the other hand, the following won't work since this doesn't reference to wgt, when doIt is called. ```ts setInterval(wgt.doIt, 1000); //WRONG! doIt will not be called with wgt ```

    Notice that this method caches the result so that it will return the same proxied function, if you pass the same function again.

    Type Parameters

    • A extends unknown[]

    • R

    Parameters

    • func: ((...args) => R)

      a method member of this object

        • (...args): R

        • Parameters

          • Rest ...args: A

          Returns R

    Returns ((...args) => R)

    a function that can be called as a global function (that actually have this referencing to this object).

      • (...args): R

      • Parameters

        • Rest ...args: A

        Returns R

  • proxy<A0, A, R>(func): ((arg0, ...args) => R)

  • Type Parameters

    • A0

    • A extends unknown[]

    • R

    Parameters

    • func: ((arg0, ...args) => R)
        • (arg0, ...args): R

        • Parameters

          • arg0: A0
          • Rest ...args: A

          Returns R

    Returns ((arg0, ...args) => R)

      • (arg0, ...args): R

      • Parameters

        • arg0: A0
        • Rest ...args: A

        Returns R

  • proxy<A0, A1, A, R>(func): ((arg0, arg1, ...args) => R)

  • Type Parameters

    • A0

    • A1

    • A extends unknown[]

    • R

    Parameters

    • func: ((arg0, arg1, ...args) => R)
        • (arg0, arg1, ...args): R

        • Parameters

          • arg0: A0
          • arg1: A1
          • Rest ...args: A

          Returns R

    Returns ((arg0, arg1, ...args) => R)

      • (arg0, arg1, ...args): R

      • Parameters

        • arg0: A0
        • arg1: A1
        • Rest ...args: A

        Returns R

  • proxy<A0, A1, A2, A, R>(func): ((arg0, arg1, arg2, ...args) => R)

  • Type Parameters

    • A0

    • A1

    • A2

    • A extends unknown[]

    • R

    Parameters

    • func: ((arg0, arg1, arg2, ...args) => R)
        • (arg0, arg1, arg2, ...args): R

        • Parameters

          • arg0: A0
          • arg1: A1
          • arg2: A2
          • Rest ...args: A

          Returns R

    Returns ((arg0, arg1, arg2, ...args) => R)

      • (arg0, arg1, arg2, ...args): R

      • Parameters

        • arg0: A0
        • arg1: A1
        • arg2: A2
        • Rest ...args: A

        Returns R

  • proxy<A0, A1, A2, A3, A, R>(func): ((arg0, arg1, arg2, arg3, ...args) => R)

  • Type Parameters

    • A0

    • A1

    • A2

    • A3

    • A extends unknown[]

    • R

    Parameters

    • func: ((arg0, arg1, arg2, arg3, ...args) => R)
        • (arg0, arg1, arg2, arg3, ...args): R

        • Parameters

          • arg0: A0
          • arg1: A1
          • arg2: A2
          • arg3: A3
          • Rest ...args: A

          Returns R

    Returns ((arg0, arg1, arg2, arg3, ...args) => R)

      • (arg0, arg1, arg2, arg3, ...args): R

      • Parameters

        • arg0: A0
        • arg1: A1
        • arg2: A2
        • arg3: A3
        • Rest ...args: A

        Returns R

restore

  • restore(wgt, skip): void

  • Restores the DOM elements that are detached (i.e., skipped) by skip.

    Parameters

    • wgt: Widget<HTMLElement>

      the widget being re-rendered

    • skip: undefined | HTMLElement

    Returns void

skip

  • skip(wgt, skipId?): undefined | HTMLElement

  • Skips all or subset of the descendant (child) widgets of the specified widget.

    Notice that the `skipId` argument is not used by zk.Widget#rerender. Rather it is used to simplify the overriding of this method, such that the deriving class can call back this class and to pass a different ID to skip

    If you don't want to pass a different ID (default: uuid + '-cave'), you can ignore `skipId` ```ts Object skip(zk.Widget wgt); ```

    Parameters

    • wgt: Widget<HTMLElement>

      the widget being rerendered.

    • Optional skipId: string

      the ID of the element where all its descendant elements shall be detached by this method, and restored later by restore. If not specified, uuid + '-cave' is assumed.

    Returns undefined | HTMLElement

    Default Value

    it detaches all DOM elements whose parent element is jq(skipId || (wgt.uuid + '-cave'), zk).

skipped

  • skipped(wgt, child): boolean

  • Parameters

    • wgt: Widget<HTMLElement> & {
          caption?: Widget<HTMLElement>;
      }

      the widget to re-render

    • child: Widget<HTMLElement>

      a child (descendant) of this widget.

    Returns boolean

    whether the specified child widget will be skipped by skip.

    Default Value

    returns if wgt.caption != child. In other words, it skip all children except the caption.

Static isAssignableFrom

  • isAssignableFrom(cls): boolean

  • Determines if the class by this Class object is either the same as, or is a superclass of, the class represented by the specified Class parameter. Example:

    if (klass1.isAssignableFrom(klass2)) {
    }

    Parameters

    • cls: typeof ZKObject

      the Class object to be checked, such as zk.Widget.

    Returns boolean

    true if assignable

Static isInstance

  • isInstance<T>(this, o): o is InstanceType<T>

  • Determines if the specified Object is assignment-compatible with this Class. This method is equivalent to [[zk.Object#$instanceof]. Example:

    if (klass.isInstance(obj)) {
    }

    Type Parameters

    Parameters

    • this: T
    • o: unknown

      the object to check

    Returns o is InstanceType<T>

    true if the object is an instance

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