1. What are the type of events into Salesforce Lightning
component?
a. Application
Event – Scope of this
event is throughout the lightning App and any component which has registered
for this event would get a notification.
b. Component Event– Scope of this event is within itself or the parent component
of this event, all the components declared within the parent component would
get notified of this event.
c. System Event- these are the
events fired by Salesforce’s system during the lifecycle of the lightning app.
2. What are the basic differences between Application Event and
Component Event?
Component events are
used to do communication between child and parent. They use bubbling and
capture same as used in DOM events. A change in a child component can be
communicated to the parent component via component event.
Application events are
used to communicate any change in the component to a broader audience. Any
component who has registered for this event will get a notified.
To use Component Event API we use the below syntax
3. When should we use Component event and application events?
It is best to always
use a component event instead of an application event. Component events can
only be handled by components above them in the containment hierarchy, therefore,
their usage is localized to the components that need to know about them.
Application events are
best used for something that should be handled at the application level, such
as navigating to a specific record. Application events allow communication between
components that are in separate parts of the application and have no direct
containment relationship.
4. Which interface we are supposed to implement so that a
lightning component can be used as quick action?
We need to implement
the following “force: lightningQuickAction” so that we can use the component as
a Quick Action
5. Which interface we are supposed to implement so that a
lightning component can be used as a Tab?
We need to implement
the following “force:appHostable” so that we can use the component as a Tab
6. How can we use a lightning component in a VisaulForce Page?
Explain?
A Lightning component
can be embed in any webpage using a very powerful and flexible feature,
Lighting out. When used with Visualforce some complexity becomes simpler.
Lightning component can be added to Visualforce page in three steps:
1. We have to first
Add the Lightning Components for Visualforce JavaScript library to your
targetted Visualforce page using the tag.
2. Next we have to
create and refer a Lightning app which is used to the component dependencies.
3. Lastly we need to
write a JavaScript function which will finally create the the component on the
page using $Lightning.createComponent()
7. How can we call child component controller method from the
parent component controller method?
To call a child
component’s controller method, we need to first create a aura:method which is
publically accessible, aura:method is used to communicate down the containment
hierarchy i.e. parent to child. Sample code for implementing the aura method:
Component code
Controller
({
publicmethod: function(cmp, event) {
var params = event.getParam(‘arguments’);
if (params) {
var message = params. str;
console.log(“message: ” + message);
return message;
}
}
})
Calling the cild
method from parent controller
({
callchildCompMethod : function(component, event, helper) {
var childCmp = component.find(“childCompName”);
var Result =
childCmp. publicmethod (“message sent by parent component”);
console.log(“Result: ” + Result);
}
})
8. What are the different Lightning component bundles?
a. Component
b. Controller
c. Helper
d. Style
e. Document
f. Design
g. SVG
h. Rendrer
9. How to ensure FLS while working with Lightning Component?
FLS and CRUD are not
automatically enforced in the lightning component whenever any object is
referenced in the Apex Controller and the component will display the fields and
records for which the users do not have access. Therefore we should manually
enforce the FLS and CRUD in the Apex Controller, or we should try to use Lightning
Data service wherever possible because it takes care of FLS and CRUD for us.
10. How can we use Lightning Components with the Salesforce1
Mobile App ?
For this purpose we
need to first make a lightning tab which points to the lightning component we
created and then we have to include that tab in the salesforc1 Mobile
Navigation select list and the newly created tab to it.
11. Can we make a Lightning Component that shows up in both the
mobile and the desktop user interfaces?
Lightning component is
lightning experience ready by default and is also compatible in Salesforce1
App, it has a responsive layout therefore it adjust its resolution according
the screen size and therefore can be used on desktop as well without writing
any separate code.
12. Is Lightning component framework an MVC framework ?
No it is not a MVC
framework it is a component based framework and event driven.
13. Which parts of Lightning Components are server-side and
which are client-side ?
Lightning components
have two types of controller, one which uses javascript and responds to the
event occurring in the components at client side and the second controller
which is an apex class. Method of apex controller are accessed by the
JavaScript controller methods asynchronously.
14. Can we make one component inherit styles/CSS from a parent
component, or must we always define it in the component ?
Child component
inherits the CSS from its aren’t we do not need to specify it for each
component
15. What is the use of the aura:method tag in Lightning ?
aura:method is used to
communicate down the containment hierarchy i.e. parent to child
16. Can we Include One Lightning component to another ?
Yes we can include one
Lightning component in another Lightning component
17. Is there any limit on how many component to have in one
Application?
There is no limit on
number of components defined within an application by salesforce
18. Is Lightning Components replacing Visualforce?
No Lightning component
is not replacing Visualforce, Visualforce is still supported by Salesforce.
19. What is Aura? Why do we use the aura: namespace in the code?
Aura is a UI framework
for developing dynamic web apps for mobile and desktop devices. Aura provides a
scalable long-lived lifecycle to support building apps engineered for growth.
Aura supports
partitioned multi-tier component development that bridges the client and
server. It uses JavaScript on the client side and Java on the server side.
20. Do we need a namespace to develop Lightning Components?
You can have namespace
in your org but it is not necessary to have a namespace to develop lightning
component.
21. What are the tools included in lightning?
Lightning App Builder – It is a tool with User interface to use
drag and drop functionality and create app fast by reusing the components,
components can be standard or custom depending upon your requirement.
Lightning Component Framework- it
provides a bundle that can be used to build reusable custom components,
Standalone App and to customize Salesforce1 App
Lightning Connect – it is a powerful tool to facilitate the integration of
force.com app with an external data source using OData specification
Lightning Process Builder – it is a
visualization tool to build automation required for your business processes.
Lightning Schema Builder – it is a
visualizing tool to view, create objects fields and relationship among them.
22. What is difference between Visualforce Components and
Lightning Components?
Visualforce page is
created keeping page as the center of the application and most of its
calculation is performed at the server side. Lightning component on the other
hand are created using the component based framework, most of the calculations
are performed at the client side and makes the more dynamic and provide rich
customer experience, also lightning component are build using mobile first
approach.
23. Does Lightning work with Visualforce ?
Yes Lightning
component works with Visualforce by implementing Lightning out as discussed
earlier.
24. Are there any CSS (styles) provided by salesforce.com as
part of the supported Lightning Components ?
Salesforce has
provided lightning design system as the default css to be used with Lightning
component.
25. Are Lightning Components intended only for mobile apps?
Although lightning
framework creates component keeping mobile first approach, but its responsive
design helps in providing the same experience over the desktop without writing
separate lines of code
26. What are the advantages of lightning?
There are many
advantages of using lightning like its out of the box component set which
enables the fast paced creation of new apps, its event driven architecture
which enables the easy decoupling between the components. Device awareness,
cross browser compatibility and framework optimized for the performance.
27. Can we integrate Lightning components with another
framework, such as Angular?
Yes we can integrate
lightning with any 3rd party framework.
28. Can we include external JavaScript/CSS libraries in
components?
It is possible to use
custom CSS and JAvascriipt in the Lightning component
29. What happens with existing Visualforce Pages in Lightning
Experience?
Most of the
Visualforce page can be easily converted to lightning experience, but they are
still supported by the salesforce and are not required to be converted
30. Where we can display lightning component?
Lightning component
can be displayed at following places:
1. Lightning Experience
2. Salesforce1 App
3. Template-based Community
4. Standalone Lightning App
5. Visualforce Pages (Using Lightning out )
31. Do I always create an app bundle first when develop
lightning component ?
No it is not necessary
to create an Appp Bundle first to develop the lightning component
32. How can we deploy components to production org?
Lightning component
can be deployed to the production via change sets, force.com IDE, Managed
Package.
33. What is Lightning Experience?
It is the new user
Interface developed by salesforce team, which is built on component based
framework and event driven architecture, which provides a dynamic and
responsive Experience to the user. This framework is built to provide optimum
performance by using stateful Client side and stateless Server architecture
34. What is the use of implements in lightning component?
Implements is use to
refer platform interfaces which enables a component to be used in different
contexts or to grant access to extra context data, a component can implement
more than one interfaces.
35. What is aura:registerevent in lightning component?
aura:registerevent is
the notifier component and it declares that it may fire a particular event, it
includes ‘name’ attribute which is relevant only to component event and is not
used for application event. Other attribute is the ‘type’ which lets the
component know which event would be fired.
Ex. <aura:registerEvent
name=”Event” type=”c:EventName”/>
36. How can we subscribe to an event in lightning component?
To subscribe to an
event in lightning component we need to include tag in the containment
hierarchy. Subscription of these event depends on the event type i.e. component
event or application event. For Component event we write below code.
In this ‘name’
attribute in should be exactly as name attribute in tag in the component which
has fired the component. The ‘action’ attribute of sets the client-side
controller action to handle the event. The ‘event’ attribute specifies the
event being handled.
For Handling Application event we write below code
‘Event’ and ‘action’
attribute are same as the component event handling, it is just that we do not
include ‘name’ attribute to handle the application event.
37. How can we communicate between two component?
In Lightning Component
Framework, the communication between two component is accompalished supported
in several ways.
1. Attributes or Methods to pass data down the component hierarchy
2. Lightning Events to pass data up and around in the component hierarchy
38. What is aura definition bundle?
It represents a
Lightning definition bundle, it contains a Lightning definition and all its
related resources. It could define a component, application, event, interface,
or a tokens collection.
An
AuraDefinitionBundle component is a collection of component definition files,
each representing a different resource such as markup code, event
documentations, applications and interfaces.
Lightning bundles must
be under a top-level folder that’s named aura. Each bundle must have its own
subfolder under the aura folder.
A bundle doesn’t have
a suffix but definition files can have one of these suffixes
Suffix Component Type
|
Suffix
|
Component Type
|
|
.app
|
Application
|
|
.cmp
|
Component
|
|
.design
|
Design
|
|
.evt
|
Event
|
|
.intf
|
Interface
|
|
.js
|
Controller, Helper,
or Renderer
|
|
.svg
|
SVG image
|
|
.css
|
Style
|
|
.auradoc
|
Documentation
|
|
.tokens
|
Tokens collection
|
39. What is aura:attribute?
They are same as
member variable in apex classes, they are typed fields and are instance of a
component. Attribute helps in making component more dynamic.
All attributes have a
name and a type can be marked required by specifying ‘required=true’and can
also have a default value. It has a naming rule as well:
1. Must begin with a
letter or an underscore
2. Must contain only alphanumeric or underscore characters
40. What is lightning: or ui: in any lightning component?
Lightning has provided
us with common User Interface components in the ui namespace which are used in
the lightning component framework. They are ui:input and ui:output provide easy
to implement common user interface.
Component with lightning namespace also provides us with the user interface but
on top of that they include lightning design system CSS by default so we do not
have to worry about the styling of these components.
41.
How can we extend any component?
To make a component
extendable we need to set value of ‘extensible’ attribute as ‘true’ of the
aura:component tag.
When a component extends another component it inherits all of the helper
methods and attributes
42. How to register, fire and handle a component and application
event?
We register an event by by using the following code
<aura:registerEvent
name=”sampleComponentEvent” type=”c:compEvent”/>
We fire event as shown
below:
var compEvent =
cmp.getEvent(“sampleComponentEvent”);
compEvent.fire();
Handle component event
as below :
<aura:handler
name=”sampleComponentEvent” event=”ns:eventName”
action=”{!c.handleComponentEvent}” phase=”capture” />
Handle Application
event as below:
<aura:handler
event=”c:appEvent” action=”{!c.handleApplicationEvent}”/>
43. Let’s say that you have an app myApp.app that contains a
component myCmp.cmp with a ui:button component. During initialization, the
init() event is fired in what order?
ui:button, ui:myCmp,
and myApp.app.
44. Why do we use @AuraEnabled annotation?
The AuraEnabled
annotation provides support for Apex methods and properties to be used with the
Lightning Component framework.
The AuraEnabled annotation is overloaded, and is used for two separate and
distinct purposes.
1. Use @AuraEnabled on Apex class static methods to make them accessible as
remote controller actions in your Lightning components.
2. Use @AuraEnabled on Apex instance methods and properties to make them
serializable when an instance of the class is returned as data from a
server-side action.
45. Why do we use $A.enqueueAction(action)?
It adds the
server-side controller action to the queue of actions to be executed. Rather
than sending a separate request for each individual action, the framework
processes the event chain and batches the actions in the queue into one
request. The actions are asynchronous and have callbacks.
46. Use of THIS CSS class?
This adds namespacing
to CSS and helps prevent one component’s CSS from blowing away another
component’s styling.
47. What are the different ways to conditionally display markup,
and what is the preferred approach?
Using the
<aura:if> tag
Use CSS to toggle visibility of markup by calling $A.util.toggleClass(cmp,
‘class’) in JavaScript code.
47. What is $Resource global value provider? Is it possible to
obtain a reference to a static resource in Javascript code?
It lets you reference
images, style sheets, and JavaScript code you’ve uploaded in static resources.
To obtain a reference
to a static resource in JavaScript code, use $A.get(‘$Resource.resourceName’).
48. Let’s say you have several buttons that reuse the same
onclick handler. How will you retrieve the name of the button that fired the
event?
Use event.getSource()
in the client-side controller to get the button component that was clicked.
Call
getLocalId() to get
the aura:id of the clicked button.
49. What are the names of interfaces that are added to a
Lightning component to allow it to be used as custom tabs, and to be used in
Lightning and Community builder?
‘force:appHostable’
Allows a component to be used as a custom tab in Lightning Experience or the
Salesforce app
‘forceCommunity:availableForAllPageTypes’ To appear in Community Builder, a
component must implement the forceCommunity:availableForAllPageTypes interface
50. What is the use of force:hasRecordId interface?
Add the
force:hasRecordId interface to a Lightning component to enable the component to
be assigned the ID of the current record.
The recordId attribute is set only when you place or invoke the component in a
context of a record. For example, when you place the component on a record
page, or invoke it as an action from a record page or object home. In all other
cases, such as when you create this component programmatically inside another
component, recordId isn’t set, and your component shouldn’t depend on it.
51. What is Lightning Design System (SLDS)?
The Salesforce
Lightning Design System (SLDS) component library is actively developed to enable
Salesforce developers to create a uniform look and feel across all
Salesforce-related applications while adhering to CSS best practices and
conventions.
52. What is the use of access=“global”?
The framework enables
you to control access to your applications, attributes, components, events,
interfaces, and methods via the access system attribute. The access system
attribute indicates whether the resource can be used outside of its own
namespace.
You can specify these values for the access system attribute.
Private: Available
within the component, app, interface, event, or method and can’t be referenced
outside the resource. This value can only be used for or .Marking an attribute
as private makes it easier to refactor the attribute in the future as the attribute
can only be used within the resource.
Accessing a private attribute returns undefined unless you reference it from
the component in which it’s declared. You can’t access a private attribute from
a sub-component that extends the component containing the private attribute.
Public: Available
within your org only. This is the default access value.
Global: Available in
all orgs.
53. What is Lightning Data Services?
They are similar to a
standard controller in Apex coding, advantages of using lightning Data service
are mentioned below
1. Use Lightning Data Service to load, create, edit, or delete a record in your
component without requiring Apex code.
2. Lightning Data Service handles sharing rules and field-level security for
you.
3. In addition to not needing Apex, Lightning Data Service improves performance
and user interface consistency.
54. What are Local and Global ids with respect to lightning
component?
Component IDs
A component has two types of IDs: a local ID and a global ID. You can retrieve
a component using its local ID in your JavaScript code. A global ID can be
useful to differentiate between multiple instances of a component or for
debugging purposes.
Local IDs
A local ID is an ID that is only scoped to the component. A local ID is often
unique but it’s not required to be unique.
Create a local ID by using the aura:id attribute. For example:
Find the button component by calling cmp.find(“button1”) in your client-side
controller, where cmp is a reference to the component containing the button.
Global IDs
Every component has a unique globalId, which is the generated runtime-unique ID
of the component instance. A global ID (1) is not guaranteed to be the same
beyond the lifetime of a component, so it should never be relied on. A global
ID can be useful to differentiate between multiple instances of a component or
for debugging purposes.
55. What is a
FlexiPage in lightning?
FlexiPage
Represents the metadata associated with a Lightning page. A Lightning page
represents a customizable screen made up of regions containing Lightning
components.
A Lightning page region can contain upto 25 components.
Lightning pages are
referred as FlexiPages in API and referred as Lightning pages elsewhere in SFDC
documentation
56. How to make quick lightning action?
Add the
force:lightningQuickAction or force:lightningQuickActionWithoutHeader interface
to a Lightning component to enable it to be used as a custom action in
Lightning Experience or the Salesforce mobile app. You can use components that
implement one of these interfaces as object-specific or global actions in both
Lightning Experience and the Salesforce app.
57. What are value providers in Salesforce Lightning ?
Value providers helps use to access data in Lightning Application .They are two
value providers as v(View) and c(controller)
v is component attribute set which helps to access component attribute values
in markup
c is component controller helps us to link with event handlers and action for
the component
58. List of Global value providers?
$globalID
$Browser
$Label
$Locale
$Resource
59. What are list of tools are avaliable in salesforce lightning
?
Lightning Connect
Lightning Component Framework
Lightning Schema Builder
Lightning Process Builder
Lightning App Builder
