<h2><code>ui.util.augment_attrs</code></h2>

<div class="theming-example">
    <p>
        Apply default values to the <code>attrs</code> item of the dictionary.
    </p>

    <p>
        This function is used internally inside <code>ui.util.attrs</code>. Following
        two examples are approximately the same.
    </p>

    {%- call ui.util.call(show_example) -%}
        {%- raw %}
            {%- set kwargs = {} -%}
            {%- set default_attrs = {"class": "hello"} -%}

            {{ ui.util.attrs(kwargs, default_attrs) }}
        {%- endraw %}
    {%- endcall %}

    {%- call ui.util.call(show_example) -%}
        {%- raw %}
            {%- set kwargs = {} -%}
            {%- set default_attrs = {"class": "hello"} -%}

            {%- set extended_kwargs = ui.util.augment_attrs(kwargs, default_attrs)-%}

            {{ ui.util.attrs(extended_kwargs) }}
        {%- endraw %}
    {%- endcall %}

</div>

<div class="theming-example">
    <p>
        This function can be called when macro needs to set default attributes
        before delegating call to a different macro.
    </p>

    {%- call ui.util.call(show_example) -%}
        {%- raw %}
            {%- macro button_with_id(content, id) -%}
                {%- set updated_kwargs = ui.util.augment_attrs(kwargs, {"id": id}) -%}

                {{ ui.button(content, **updated_kwargs) }}
            {%- endmacro %}

            {{ button_with_id("Click", id="test-id") }}
        {%- endraw %}
    {%- endcall %}
</div>

<div class="theming-example">
    <p>
        By default it updates <code>attrs</code> item in the dictionary, but
        you can change this behavior by providing <code>key</code> argument. If
        it's non-empty string, corresponding item will be updated. If it's a
        falsy value, the top-level will be updated
    </p>


    {%- call ui.util.call(show_example) -%}
        {%- raw %}
            {%- set data = {} -%}
            {%- do ui.util.augment_attrs(data, {"x": 1}) -%}
            {%- do ui.util.augment_attrs(data, {"y": 2}, key="aria") -%}
            {%- do ui.util.augment_attrs(data, {"z": 3}, key=none) -%}

            {{ data | tojson }}
        {%- endraw %}
    {%- endcall %}
</div>


<div class="theming-example">
    <p>
        Only missing items will be applied. If target item already contains
        value for the one of default keys, it will remain unchanged.
    </p>

    {%- call ui.util.call(show_example) -%}
        {%- raw %}
            {%- set data = {"attrs": {"a": 42}} -%}
            {%- do ui.util.augment_attrs(data, {"a": 1, "b": 2}) -%}

            {{ data | tojson }}
        {%- endraw %}
    {%- endcall %}
</div>