Styling an icon defined with prepend-icon in Vuetify

Question

Normally to style an icon in Vuetify we'll do something like

<v-icon large color="primary">comment</v-icon> 

How do we get the same effect while using the prepend-icon prop like here

<v-list-group prepend-icon="comment">

The documentation says prepend-icon uses same syntax as v-icon but no concrete example is provided for my use case

Answer 1

Target it properly and apply style.
For example in v-list-group:

.v-list__group__header__prepend-icon .v-icon {
    color: red;
}  

But note for example v-text-field append icon

.v-input__icon--append .v-icon { 
    color: purple;
}

NOTE: If it's not working, and you are using scoped styles, see how to resolve it.

Care not to use only .v-icon because for example you might override append icon as well, which might not be what you want.
Also, !important is not a good practice and we don't need to use it here.
So just rotate .v-list__group__header__prepend-icon class depending on component or even add your own class. Inspect element and see what the class is for prepend/append icon because it's not always same.
(if you are using scoped styles then perhaps there is no need for adding your own additional selectors for targeting the specific icons).

Example codepen

Note: I'm not aware of any vuetify's own classes or props for styling prepend/append icons. So if these exist or get implemented in the future, use them.

Answer 2

Using a v-icon inside the prependIcon slot of the v-list-group template (instead of the prepend-icon prop) will give you all the flexibility you need:

<v-list-group>
  <v-icon slot="prependIcon" large color="primary">comment</v-icon>
</v-list-group>

Answer 3

This may be a little late, but the proper way to apply color styling to 'fonts' (i.e. material icons) using v-icon tag is using Vuetify's class system.

text--{lighten|darken}-{n} https://vuetifyjs.com/en/styles/colors#classes

<v-icon class="primary--text">comment</v-icon>
<v-icon class="red--text">comment</v-icon>
<v-icon class="green--text lighten-3">comment</v-icon>

You can define primary, secondary, {custom}... theme colors in your Vuetify constructor.