An accordion organizes related content into expandable and collapsible sections, reducing page scrolling and helping users focus on relevant information. Each section has a trigger button and a content panel. Clicking a trigger toggles the visibility of its associated panel.
import {Component} from '@angular/core';
import {
AccordionGroup,
AccordionTrigger,
AccordionPanel,
AccordionContent,
} from '@angular/aria/accordion';
@Component({
selector: 'app-root',
templateUrl: 'app.html',
styleUrl: 'app.css',
imports: [AccordionGroup, AccordionTrigger, AccordionPanel, AccordionContent],
})
export class App {}
<div ngAccordionGroup class="basic-accordion" [multiExpandable]="false">
<h3>
<span ngAccordionTrigger [panel]="panel1" #trigger1="ngAccordionTrigger" [expanded]="true">
Which attribute tells assistive tech whether the panel is open or closed?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger1.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel1="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use <code>aria-expanded</code> on the button element. Set it to "true" when the content
panel is visible and "false" when the content is hidden. This is a crucial state indicator
for screen reader users.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel2" #trigger2="ngAccordionTrigger">
How do you link the button to the content it controls?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger2.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel2="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use the <code>aria-controls</code> attribute on the button, and set its value to match the
id of the related content panel. This establishes a programmatic relationship, allowing
assistive technologies to jump directly to the relevant content.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel3" #trigger3="ngAccordionTrigger">
What role should the heading element containing the accordion button have?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger3.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel3="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
The element containing the button should typically have <code>role="heading"</code> with an
appropriate <code>aria-level</code> to define the structure. This ensures the accordion
section is recognized as a section header, making the page structure navigable for users.
</p>
</ng-template>
</div>
</div>
Accordions work well for organizing content into logical groups where users typically need to view one section at a time.
Use accordions when:
Displaying FAQs with multiple questions and answers
Organizing long forms into manageable sections
Reducing scrolling on content-heavy pages
Progressively disclosing related information
Avoid accordions when:
Building navigation menus (use the Menu component instead)
Creating tabbed interfaces (use the Tabs component instead)
Showing a single collapsible section (use a disclosure pattern instead)
Users need to see multiple sections simultaneously (consider a different layout)
Features
Expansion modes - Control whether one or multiple panels can be open at the same time
Keyboard navigation - Navigate between triggers using arrow keys, Home, and End
Lazy rendering - Content is only created when a panel first expands, improving initial load performance
Disabled states - Disable the entire group or individual triggers
Focus management - Control whether disabled items can receive keyboard focus
Programmatic control - Expand, collapse, or toggle panels from your component code
RTL support - Automatic support for right-to-left languages
Examples
Single expansion mode
Set [multiExpandable]="false" to allow only one panel to be open at a time. Opening a new panel automatically closes any previously open panel.
import {Component} from '@angular/core';
import {
AccordionGroup,
AccordionTrigger,
AccordionPanel,
AccordionContent,
} from '@angular/aria/accordion';
@Component({
selector: 'app-root',
templateUrl: 'app.html',
styleUrl: 'app.css',
imports: [AccordionGroup, AccordionTrigger, AccordionPanel, AccordionContent],
})
export class App {}
<div ngAccordionGroup class="basic-accordion" [multiExpandable]="false">
<h3>
<span ngAccordionTrigger [panel]="panel1" #trigger1="ngAccordionTrigger" [expanded]="true">
Which attribute tells assistive tech whether the panel is open or closed?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger1.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel1="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use <code>aria-expanded</code> on the button element. Set it to "true" when the content
panel is visible and "false" when the content is hidden. This is a crucial state indicator
for screen reader users.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel2" #trigger2="ngAccordionTrigger">
How do you link the button to the content it controls?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger2.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel2="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use the <code>aria-controls</code> attribute on the button, and set its value to match the
id of the related content panel. This establishes a programmatic relationship, allowing
assistive technologies to jump directly to the relevant content.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel3" #trigger3="ngAccordionTrigger">
What role should the heading element containing the accordion button have?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger3.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel3="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
The element containing the button should typically have <code>role="heading"</code> with an
appropriate <code>aria-level</code> to define the structure. This ensures the accordion
section is recognized as a section header, making the page structure navigable for users.
</p>
</ng-template>
</div>
</div>
import {Component} from '@angular/core';
import {
AccordionGroup,
AccordionTrigger,
AccordionPanel,
AccordionContent,
} from '@angular/aria/accordion';
@Component({
selector: 'app-root',
templateUrl: 'app.html',
styleUrl: 'app.css',
imports: [AccordionGroup, AccordionTrigger, AccordionPanel, AccordionContent],
})
export class App {}
<div ngAccordionGroup class="material-accordion" [multiExpandable]="false">
<h3>
<span ngAccordionTrigger [panel]="panel1" #trigger1="ngAccordionTrigger">
Which attribute tells assistive tech whether the panel is open or closed?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger1.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel1="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use <code>aria-expanded</code> on the button element. Set it to "true" when the content
panel is visible and "false" when the content is hidden. This is a crucial state indicator
for screen reader users.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel2" #trigger2="ngAccordionTrigger" [expanded]="true">
How do you link the button to the content it controls?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger2.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel2="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use the <code>aria-controls</code> attribute on the button, and set its value to match the
id of the related content panel. This establishes a programmatic relationship, allowing
assistive technologies to jump directly to the relevant content.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel3" #trigger3="ngAccordionTrigger">
What role should the heading element containing the accordion button have?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger3.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel3="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
The element containing the button should typically have <code>role="heading"</code> with an
appropriate <code>aria-level</code> to define the structure. This ensures the accordion
section is recognized as a section header, making the page structure navigable for users.
</p>
</ng-template>
</div>
</div>
This mode works well for FAQs or situations where you want users to focus on one answer at a time.
Multiple expansion mode
Set [multiExpandable]="true" to allow multiple panels to be open simultaneously. Users can expand as many panels as needed without closing others.
import {Component} from '@angular/core';
import {
AccordionGroup,
AccordionTrigger,
AccordionPanel,
AccordionContent,
} from '@angular/aria/accordion';
@Component({
selector: 'app-root',
templateUrl: 'app.html',
styleUrl: 'app.css',
imports: [AccordionGroup, AccordionTrigger, AccordionPanel, AccordionContent],
})
export class App {}
<div ngAccordionGroup class="basic-accordion">
<h3>
<span ngAccordionTrigger [panel]="panel1" #trigger1="ngAccordionTrigger" [expanded]="true">
Which attribute tells assistive tech whether the panel is open or closed?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger1.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel1="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use <code>aria-expanded</code> on the button element. Set it to "true" when the content
panel is visible and "false" when the content is hidden. This is a crucial state indicator
for screen reader users.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel2" #trigger2="ngAccordionTrigger">
How do you link the button to the content it controls?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger2.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel2="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use the <code>aria-controls</code> attribute on the button, and set its value to match the
id of the related content panel. This establishes a programmatic relationship, allowing
assistive technologies to jump directly to the relevant content.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel3" #trigger3="ngAccordionTrigger" [expanded]="true">
What role should the heading element containing the accordion button have?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger3.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel3="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
The element containing the button should typically have <code>role="heading"</code> with an
appropriate <code>aria-level</code> to define the structure. This ensures the accordion
section is recognized as a section header, making the page structure navigable for users.
</p>
</ng-template>
</div>
</div>
import {Component} from '@angular/core';
import {
AccordionGroup,
AccordionTrigger,
AccordionPanel,
AccordionContent,
} from '@angular/aria/accordion';
@Component({
selector: 'app-root',
templateUrl: 'app.html',
styleUrl: 'app.css',
imports: [AccordionGroup, AccordionTrigger, AccordionPanel, AccordionContent],
})
export class App {}
<div ngAccordionGroup class="material-accordion">
<h3>
<span ngAccordionTrigger [panel]="panel1" #trigger1="ngAccordionTrigger" [expanded]="true">
Which attribute tells assistive tech whether the panel is open or closed?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger1.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel1="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use <code>aria-expanded</code> on the button element. Set it to "true" when the content
panel is visible and "false" when the content is hidden. This is a crucial state indicator
for screen reader users.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel2" #trigger2="ngAccordionTrigger">
How do you link the button to the content it controls?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger2.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel2="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use the <code>aria-controls</code> attribute on the button, and set its value to match the
id of the related content panel. This establishes a programmatic relationship, allowing
assistive technologies to jump directly to the relevant content.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel3" #trigger3="ngAccordionTrigger" [expanded]="true">
What role should the heading element containing the accordion button have?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger3.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel3="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
The element containing the button should typically have <code>role="heading"</code> with an
appropriate <code>aria-level</code> to define the structure. This ensures the accordion
section is recognized as a section header, making the page structure navigable for users.
</p>
</ng-template>
</div>
</div>
This mode is useful for form sections or when users need to compare content across multiple panels.
NOTE: The multiExpandable input defaults to true. Set it to false explicitly if you want single expansion behavior.
Disabled accordion items
Disable specific triggers using the disabled input. Control how disabled items behave during keyboard navigation using the softDisabled input on the accordion group.
import {Component} from '@angular/core';
import {
AccordionGroup,
AccordionTrigger,
AccordionPanel,
AccordionContent,
} from '@angular/aria/accordion';
@Component({
selector: 'app-root',
templateUrl: 'app.html',
styleUrl: 'app.css',
imports: [AccordionGroup, AccordionTrigger, AccordionPanel, AccordionContent],
})
export class App {}
<div ngAccordionGroup class="basic-accordion">
<h3>
<span ngAccordionTrigger [panel]="panel1" #trigger1="ngAccordionTrigger" [expanded]="true">
Which attribute tells assistive tech whether the panel is open or closed?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger1.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel1="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use <code>aria-expanded</code> on the button element. Set it to "true" when the content
panel is visible and "false" when the content is hidden. This is a crucial state indicator
for screen reader users.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel2" #trigger2="ngAccordionTrigger" disabled>
How do you link the button to the content it controls?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger2.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel #panel2="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use the <code>aria-controls</code> attribute on the button, and set its value to match the
id of the related content panel. This establishes a programmatic relationship, allowing
assistive technologies to jump directly to the relevant content.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel3" #trigger3="ngAccordionTrigger">
What role should the heading element containing the accordion button have?
<span
aria-hidden="true"
class="expand-icon"
[class.expand-icon__expanded]="trigger3.expanded()"
></span>
</span>
</h3>
<div ngAccordionPanel panelId="q3" #panel3="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
The element containing the button should typically have <code>role="heading"</code> with an
appropriate <code>aria-level</code> to define the structure. This ensures the accordion
section is recognized as a section header, making the page structure navigable for users.
</p>
</ng-template>
</div>
</div>
import {Component} from '@angular/core';
import {
AccordionGroup,
AccordionTrigger,
AccordionPanel,
AccordionContent,
} from '@angular/aria/accordion';
@Component({
selector: 'app-root',
templateUrl: 'app.html',
styleUrl: 'app.css',
imports: [AccordionGroup, AccordionTrigger, AccordionPanel, AccordionContent],
})
export class App {}
<div ngAccordionGroup class="material-accordion">
<h3>
<span ngAccordionTrigger [panel]="panel1" #trigger1="ngAccordionTrigger" [expanded]="true">
Which attribute tells assistive tech whether the panel is open or closed?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger1.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel1="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use <code>aria-expanded</code> on the button element. Set it to "true" when the content
panel is visible and "false" when the content is hidden. This is a crucial state indicator
for screen reader users.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel2" #trigger2="ngAccordionTrigger" disabled>
How do you link the button to the content it controls?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger2.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel2="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
Use the <code>aria-controls</code> attribute on the button, and set its value to match the
id of the related content panel. This establishes a programmatic relationship, allowing
assistive technologies to jump directly to the relevant content.
</p>
</ng-template>
</div>
<h3>
<span ngAccordionTrigger [panel]="panel3" #trigger3="ngAccordionTrigger">
What role should the heading element containing the accordion button have?
<span
aria-hidden="true"
class="material-symbols-outlined expand-icon"
[class.expand-icon__expanded]="trigger3.expanded()"
translate="no"
>keyboard_arrow_up</span
>
</span>
</h3>
<div ngAccordionPanel #panel3="ngAccordionPanel">
<ng-template ngAccordionContent>
<p>
The element containing the button should typically have <code>role="heading"</code> with an
appropriate <code>aria-level</code> to define the structure. This ensures the accordion
section is recognized as a section header, making the page structure navigable for users.
</p>
</ng-template>
</div>
</div>
When [softDisabled]="true" (the default), disabled items can receive focus but cannot be activated. When [softDisabled]="false", disabled items are skipped entirely during keyboard navigation.
Lazy content rendering
Use the ngAccordionContent directive on an ng-template to defer rendering content until the panel first expands. This improves performance for accordions with heavy content like images, charts, or complex components.
<div ngAccordionGroup>
<div>
<button ngAccordionTrigger [panel]="panel1">Trigger Text</button>
<div ngAccordionPanel #panel1="ngAccordionPanel">
<ng-template ngAccordionContent>
<!-- This content only renders when the panel first opens -->
<img src="large-image.jpg" alt="Description" />
<app-expensive-component />
</ng-template>
</div>
</div>
</div>
By default, content remains in the DOM after the panel collapses. Set [preserveContent]="false" to remove the content from the DOM when the panel closes.
Testing
Angular Aria provides component harnesses for testing accordion components. Here is an example of how to use the harnesses in a component test:
import {ComponentFixture, TestBed} from '@angular/core/testing';
import {HarnessLoader} from '@angular/cdk/testing';
import {TestbedHarnessEnvironment} from '@angular/cdk/testing/testbed';
import {AccordionGroupHarness} from '@angular/aria/accordion/testing';
import {MyAccordionComponent} from './my-accordion'; // Your component
describe('MyAccordionComponent', () => {
let fixture: ComponentFixture<MyAccordionComponent>;
let loader: HarnessLoader;
beforeEach(async () => {
TestBed.configureTestingModule({
imports: [MyAccordionComponent],
});
fixture = TestBed.createComponent(MyAccordionComponent);
await fixture.whenStable();
loader = TestbedHarnessEnvironment.loader(fixture);
});
it('should allow expanding panels', async () => {
// Load the accordion group harness
const group = await loader.getHarness(AccordionGroupHarness);
// Get all individual accordions (items) in the group
const accordions = await group.getAccordions();
expect(accordions.length).toBe(3);
// Verify initial state (first expanded, others collapsed)
expect(await accordions[0].isExpanded()).toBe(true);
expect(await accordions[1].isExpanded()).toBe(false);
// Expand the second panel
await accordions[1].expand();
// Verify updated state
expect(await accordions[1].isExpanded()).toBe(true);
// If multiExpandable is false, the first one should now be collapsed
expect(await accordions[0].isExpanded()).toBe(false);
});
});
APIs
AccordionGroup
The container directive that manages keyboard navigation and expansion behavior for a group of accordion items.
Inputs
Property
Type
Default
Description
disabled
boolean
false
Disables all triggers in the group
multiExpandable
boolean
true
Whether multiple panels can be expanded simultaneously
softDisabled
boolean
true
When true, disabled items are focusable. When false, they are skipped
wrap
boolean
false
Whether keyboard navigation wraps from last to first item and vice versa
Methods
Method
Parameters
Description
expandAll
none
Expands all panels (only works when multiExpandable is true)
collapseAll
none
Collapses all panels
AccordionTrigger
The directive applied to the button element that toggles panel visibility.
