The aura:valueChange event is used to handle attribute value change in lightning components in Salesforce.


Sample Code:


Component:


<aura:component implements=”force:appHostable”>
    
    <aura:handler name=”change” value=”{!v.strText}” action=”{!c.handleValueChange}”/>
    
    <aura:attribute name=”strText” type=”string” default=”Sample”/>
    
    <div class=”slds-box slds-theme_default”>
        <lightning:input value=”{!v.strText}” type=”text” label=”Text”/><br/>
        <lightning:button variant=”brand” label=”Update” onclick=”{!c.clickIt}”/>
    </div>
    
</aura:component>



Controller:


({
    clickIt : function(component, event, helper) {
        component.set(“v.strText”, “Changing”);
    },
    
    handleValueChange : function (component, event, helper) {
        alert(“Changed strText ” + component.get(“v.strText”));
    }
})



Output: