So I have this field input in my UI, I need it to throw an error if it is left blank, but it is not. This is my code

<div class="slds-text-heading_medium slds-align_absolute-center">
        <lightning:input aura:id="matrixName" name="Matrix Name" maxlength="80"
                         label="Matrix Name" placeholder="Matrix Name" />
        <aura:if isTrue="{!not(empty(v.inputError))}">

My controller

doCreateMatrix: function (component) {
    var matrixInput = component.find("matrixName");

    if (!matrixInput) {
        console.log("matrixName has not been found");

    var matrixName = matrixInput.get('v.value');

    if (!matrixName || matrixName.trim().length === 0) {
        //Handle BLANK matrixName
        component.set("v.inputError", "Name cannot be blank");
  • 3
    Why not just use required="true"? The component can validate itself. – sfdcfox Mar 27 at 19:32
  • I added the the condition required="true", should I remove the aura:if because it is still not showing my error message, I added what I have in my controller – Deja Bond Mar 27 at 19:43

The standard method is to let the component validate itself:

    <lightning:input aura:id="matrixName" name="Matrix Name" maxlength="80"
                     label="Matrix Name" placeholder="Matrix Name" 
                     required="true" />

This will also add the required askerisk (a red *) to the field's label, indicating it is required.

In your code, make sure you check validity before submitting data to the server:

var matrixField = component.find("matrixName");
if(!matrixField.checkValidity()) {
  // Optional message if you want
  alert("Please fill out the required field."); 
  return; // Don't continue past this point
  • Yea for some reason, the alert is not appearing on screen, I have exactly what you have – Deja Bond Mar 27 at 20:01
  • I think I discovered why, Ill share shortly – Deja Bond Mar 27 at 20:21
  • i had to add the attribute to my original code <aura:attribute name="inputError" type="String" default="" /> – Deja Bond Mar 27 at 20:35

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