vue-select/docs/guide/upgrading.md

Removed Function Callbacks

Three function callbacks have been removed in favor of using events.

• onChange
• onInput
• onSearch

While this is a breaking change, the change in your application should be as simple as swapping the prop you were using for an event.

onChange & onInput

In v2.x, Overwriting onChange in an application was more likely to break vue-select's internals and cause issues. The input event provides identical functionality and can be swapped out in your application.

<!-- version 2: -->
<v-select :on-change="doSomething" />

<!-- version 3: -->
<v-select @input="doSomething" />

Additionally, the change event has been removed. This event was redundant, input should be used instead.

<!-- version 2: -->
<v-select @change="doSomething" />

<!-- version 3: -->
<v-select @input="doSomething" />

onSearch

The onSearch prop was removed for the same reason as onChange and onInput. The search event has always provided the same parameters and can be used in it's place.

<!-- version 2: -->
<v-select :on-search="doSomeAjax" />

<!-- version 3: -->
<v-select @search="doSomeAjax" />

Separated CSS

CSS was removed from the JS bundle in favor of a separate CSS file to support SSR and easier customization.

@import vSelect from 'vue-select`;
@import 'vue-select/dist/vue-select.css';

New Class Selector Prefix

In order to avoid CSS collisions and allow for low specificity overrides of CSS, all classes have been renamed to include the vs__ prefix. The full list of renamed classes are listed below:

original	renamed
.open-indicator	.vs__open-indicator
.dropdown-toggle	.vs__dropdown-toggle
.dropdown-menu	.vs__dropdown-menu
.clear	.vs__clear
.selected-tag	.vs__selected
.no-options	.vs__no-options
.spinner	.vs__spinner
.close	.vs__deselect
.active	.vs__active

Internal State

The changes listed below are very unlikely to break your apps unless you've been hooking into vue-select internal values. #781 (thanks @owenconti!) introduced a number of optimizations to the way that the component handles internal state.

• value: the value prop is undefined by default. vue-select no longer maintains an internal mutableValue state when a value prop has been passed. When :value or v-model is not used, vue-select will maintain internal state using the _value property.
• mutableOptions has been removed in favor of an optionList computed property.

Misc

• fade transition renamed to vs__fade
• Removed a element that was serving as the click handler within dropdown options