Why is component.find().getElement() undefined in Aura Components?
When working with Aura components, developers often encounter situations where component.find().getElement() returns undefined or becomes inaccessible, especially after setting breakpoints or using debugger statements in the init event handler. This issue became more noticeable after the Winter ’17 release when Locker Service was fully enforced. The problem is tied to how the Lightning Component Framework handles the component lifecycle and DOM rendering phases.
Let’s understand the scenario with an example. Consider this component structure:
<aura:component>
<aura:handler name="init" value="{!this}" action="{!c.doInit}"/>
<select aura:id="select-element" class="slds-select" onchange="{!c.handleSelect}"></select>
</aura:component>
Here, the controller method doInit is defined as follows:
({
doInit : function(component, event, helper) {
// Perform initialization logic
debugger; // pause execution
}
})
When a debugger statement or a manual breakpoint is triggered during initialization, the execution pauses at a very early phase in the component lifecycle—specifically before the DOM elements are fully available. This means that if you try to access the DOM element using component.find("select-element").getElement() right after this point, it will return undefined. This happens because the rendering phase has not completed yet.
Locker Service enforces strict separation of component namespaces for security. Therefore, even if the DOM node physically exists later, Locker Service prevents your custom component (in the c namespace) from directly accessing the underlying DOM elements of standard Lightning components (in the lightning namespace). For example, if you try to use cmp.find("myButton").getElement() on a lightning:button, it will fail due to Locker Service restrictions.
To fix this issue, you must access DOM elements at the correct point in the component lifecycle—specifically after rendering is completed. The proper approach is to use the afterRender() method inside a custom renderer. The afterRender() method is invoked after the component’s DOM has been fully rendered, ensuring that getElement() is available.
Here’s how you can modify the component to safely access DOM elements:
Renderer.js:
({
afterRender: function(component, helper) {
this.superAfterRender();
// Safe to access DOM elements here
var element = component.find("select-element").getElement();
console.log('DOM Element:', element);
}
})
In this code, the superAfterRender() method ensures that the base rendering logic executes before your custom logic. After this, the DOM element is guaranteed to exist, so calling getElement() will work reliably.
In summary, this issue arises due to the timing of DOM availability within the Lightning Component lifecycle and the restrictions imposed by Locker Service. Using component.find().getElement() inside init is not recommended because elements are not yet rendered. Instead, always use the afterRender() lifecycle hook for safe DOM manipulation. Additionally, remember that Locker Service prevents cross-namespace DOM access, so direct DOM manipulation on standard Lightning components like lightning:button is not allowed from custom components.
The Root Cause: Component Lifecycle and Timing
Every Aura component goes through several lifecycle phases:
- Initialization (
init) – The component is being created, attributes are set, but DOM elements are not yet rendered. - Rendering – The framework begins creating DOM nodes for the component.
- After Render (
afterRender) – The DOM is now available and can be safely accessed. - Rerender and Unrender – These occur later when component state changes or when it’s destroyed.
When you use the init handler, the component has not yet finished rendering. The elements defined in your markup (<select>, <div>, etc.) are still being constructed by the framework. Therefore, calling:
component.find("select-element").getElement();
inside doInit() is premature — there’s no guarantee the browser has built the DOM element yet. Even though your markup looks ready, under the hood, Aura hasn’t inserted it into the DOM tree.
Now, when you place a debugger statement or a manual breakpoint, you’re freezing JavaScript execution. That disrupts the framework’s internal event loop and rendering flow, leading to an incomplete state where the element reference (getElement()) never becomes accessible. This is a timing issue, not a syntax or Locker Service bug.
Why debugger or Breakpoints Cause “Destructive Interference”
When you hit a breakpoint in doInit, Aura’s rendering pipeline gets paused before DOM nodes are finalized. Resuming from the breakpoint may not restart the rendering flow in the same sequence, which can leave the component’s internal references partially uninitialized. So, even if the DOM element eventually appears in the browser, the Aura proxy object that connects your component to its DOM counterpart isn’t linked properly. Hence, component.find("select-element").getElement() remains undefined.
The Role of Locker Service
Locker Service enforces strict security boundaries in Lightning to prevent cross-component or cross-namespace DOM access.
Each component runs in its own “secure sandbox.” This means a custom component (c:MyComponent) cannot directly access the DOM of a standard Lightning component (lightning:button, lightning:input, etc.).
For example:
cmp.find("myButton").getElement(); // ❌ Fails for lightning:button
This fails because lightning:button belongs to the Lightning namespace, while your component belongs to the c namespace. Locker Service blocks such cross-namespace access to prevent injection or manipulation attacks.
You can, however, safely use getElement() on your own component’s DOM nodes, as long as:
- The element belongs to the same namespace (like
c:MyComponent). - You access it after rendering is complete.
The Correct Solution: Use Custom Renderers
The best practice is to access DOM elements in the afterRender() phase, which is triggered after the component and all its child elements have been fully rendered.
({
afterRender: function(component, helper) {
this.superAfterRender(); // always call the parent implementation
var selectElem = component.find("select-element").getElement();
console.log('DOM Element:', selectElem);
// You can now manipulate the element safely
selectElem.style.border = "2px solid red";
}
})
This approach guarantees that:
- The DOM is fully available.
- The Aura framework has finished rendering.
- Locker Service permissions are respected.
In Summary
The component.find().getElement() issue occurs due to the Aura lifecycle timing and Locker Service security boundaries. The init event fires too early—before the DOM exists. A debugger or breakpoint worsens the situation by pausing rendering, leading to lost element references. The correct way is to move any DOM manipulation logic to the afterRender() method within a custom renderer, where the DOM is fully ready and accessible.
This design ensures your component works consistently, even with Locker Service enabled, and aligns with Salesforce’s best practices for secure, stable Lightning component development.
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