# AUR0716

### **Error message**

Template compilation error: duplicate definition of the local template named "{{0}}" in element "{{1}}"

### **Parameters**

1. `localElementName`: The duplicate name used in the `as-custom-element` attribute.
2. `owningElementName`: The name of the custom element whose template contains the duplicate local element definition.

### Error explanation

This error occurs during template compilation when two or more local element definitions (`<template as-custom-element="...">`) within the same parent component's template are given the same name via the `as-custom-element` attribute. Each local element defined within a parent component must have a unique name.

### Common causes

* Copy-pasting a `<template as-custom-element="...">` block and forgetting to change the name in the `as-custom-element` attribute.
* Accidentally using the same name for two different local element concepts within the same parent component.

### How to fix

* Review the `<template as-custom-element="...">` tags within the parent component's template (`{{1}}`).
* Ensure that the value provided to each `as-custom-element` attribute is unique within that template.
* Rename the duplicate local element definitions to have distinct names.

### Example of Incorrect Usage:

```html
<!-- my-component.html -->
<template>
  <local-widget></local-widget>
  <local-widget></local-widget> <!-- This will resolve to the first definition -->

  <!-- Error: Duplicate local element name "local-widget" -->
  <template as-custom-element="local-widget">
    <div>Widget Version 1</div>
  </template>
  <template as-custom-element="local-widget">
    <span>Widget Version 2</span>
  </template>
</template>
```

### Example of Correct Usage:

```html
<!-- my-component.html -->
<template>
  <local-widget-a></local-widget-a>
  <local-widget-b></local-widget-b>

  <!-- Correct: Unique names -->
  <template as-custom-element="local-widget-a">
    <div>Widget Version 1</div>
  </template>
  <template as-custom-element="local-widget-b">
    <span>Widget Version 2</span>
  </template>
</template>
```