vue-focus

vue-focus

A set of reusable focus directives for reusable Vue.js components

Overview

It can be tricky to manage input focus in your components. You always have to fall back to accessing DOM elements and calling .focus or .blur on them.

Well not anymore. vue-focus lets you manage input focus from the safety of your view model. It consists of three directives:

• v-focus-auto auto focuses the element whenever it enters the DOM;
• v-focus-model="<expression>" binds the focus to the expression in a two-way manner (model changes cause focus to adjust, and focus changes cause model to adjust);
• v-focus="<expression>" binds the focus to the expression in a one-way manner (model changes cause focus to adjust).

Why the v-focus exists when there is v-focus-model, you might ask? Well, if you use a condition or a method to determine the focus, then you can not use a two-way bound directive, as it requires the expression to be settable.

Now you are ready to check out the examples, read the docs or file an issue.

Use cases

• Focus a field when the modal appears
• Show a hint for the focused field

Requirements

• vue: ^1.0.0

Install

From npm:

$ npm install vue-focus --save

From CDN:

<script src="https://cdn.rawgit.com/simplesmiler/vue-focus/0.1.1/dist/vue-focus.js"></script>
<!-- OR -->
<script src="https://cdn.rawgit.com/simplesmiler/vue-focus/0.1.1/dist/vue-focus.min.js"></script>

Usage

1. Make directives available to your component (either by mixin or one by one)
2. Use directives on the element

API

focus

A directive that binds focus to the expression in a one-way manner, so that the element recieves focus when you set the bound value to be truthy and loses focus when you set the bound value to be falsy. It takes a single argument: an expression to be bound.

NOTE: This is a one-way bound directive. If you need a two-way bound version, please refer to focus-model.

import { focus } from 'vue-focus';

export default {
  directives: { focus: focus },
  template: '<input type="text" v-for="item in items" v-model="item.value" v-focus="$index === focused">',
  data: function() {
    return {
      focused: 0,
      items: [
        { value: 'hello' },
        { value: 'world' },
      ],
    };
  },
};

focus-model

A directive that binds focus to the expression in a two-way manner, so that the element recieves focus when you change the bound value to true and loses focus when you change the bound value to false, and vice versa, sets the bound value to true when element recieves focus and sets the bound value to false when element loses focus. It takes a single argument: an expression to be bound.

NOTE: This is a two-way bound directive. If you need a one-way bound version, please refer to focus.

NOTE: The expression has to be settable, and has to evaluate to a boolean value.

import { focusModel } from 'vue-focus';

export default {
  directives: { focusModel: focusModel },
  template: '<input type="text" v-focus-model="focused">',
  data: function() {
    return {
      focused: false,
    };
  },
};

focus-auto

A directive that makes the element gain focus whenever it enters the DOM (either via initial costruction or by the means of :is, v-if or v-for). It takes no arguments.

NOTE: This is a reactive replacement for the native html attribute autofocus, which does not work after page has finished loading.

import { focusAuto } from 'vue-focus';

export default {
  directives: { focusAuto: focusAuto },
  template: '<input type="text" v-focus-auto>',
};

mixin

A mixin that includes all the directives at once, and makes them available to the component under their default names.

import * as VueFocus from 'vue-focus';

export default {
  mixins: [ VueFocus.mixin ],
  template: '<input type="text" v-focus-model="focused" v-focus-auto>',
  data: function() {
    return {
      focused: false,
    };
  },
};

Caveats

1. Although you can write an input that gains focus immediately after loosing it, this is not recommended, as two such inputs will fall into infinite recursion and freeze the browser.
2. Prior to vue@1.0 views were able to inherit assets from the parent views, which made it possible to define the directive on the root view and have it available across the whole view hierarchy. Since vue@1.0 this is not possible. If you still want to define the directive application-wide, you should Vue.directive('<directive-name>', <directive>); in your application entry point for every directive you need. But bear in mind that this introduces implicit dependency for your components, making them less reusable.

Notes

Form elements are not the only elements that are able to receive focus. The list also includes links, element with tabindex attribute set and elements with contentEditable set to true.

License

MIT