vue-debounce

A simple to use directive for debounce solutions

It attaches itself to an event for actions

Important

As of now vue2-debounce is published on npm, if you are using vue2 I highly recommend migrating to this package as this one is going to start focusing on vue3 from v5 onward. Consider vue2 support deprecated for this module.

Content

• Features
• Installation
• Modifiers
• Options
• Option Defaults
• CDN Support
• Setup
• Use Just Debounce
• Usage
• Modifier Usage
• Overwriting Events
• Typescript Support
• Caveats

Features

• Dynamic debouncing for input based requests
• Easy to use, just place it into your vue instance and attach it to your inputs/components
• Self regulating no need to worry about it, set it and forget it
• Multiple time formats supported (miliseconds and seconds)
• Enter key support to automatically fire the desired function when the user hits the enter key in the desired input (Can also be disabled)
• Supports the ability to have multiple event listeners, and specify events at the element level

Installation

npm i vue-debounce

Modifiers

• lock : Used to lock the debounce and prevent the enter key from triggering the function when pressed
  • Example: v-debounce:400ms.lock="cb"
• unlock : Used to unlock the enter key on a debounced input, useful if you want to use the lock option and only want a few debounced inputs unlocked
• fireonempty : Use to signify that when that specific input is emptied, you want the function to fire right away
• cancelonempty : Use this to specify that when the input is emptied you DO NOT want your debounced function to trigger at all
• trim : Boolean - Tells debounce to trim out white space using the String.prototype.trim() function

Options

• lock : Boolean - This works the same way as the modifier does, however using the option will lock ALL of the debounced inputs within that vue instance, where as using the modifer only locks the one it's attached to
• listenTo : String|Array - Allows you to set a custom event attached to an element like input for example
  • This is given to the addEventListener method attached to the element
• defaultTime : String - Set the default timer for debounce directives that you don't give a time to
• fireOnEmpty : Boolean - Tells debounce that if the input is empty, then fire the function immediately
• trim : Boolean - Tells debounce to trim out white space using the String.prototype.trim() function

Option Defaults

{
  lock: false,
  listenTo: 'keyup',
  defaultTime: '300ms',
  fireOnEmpty: false,
  trim: false
}

CDN Support

You can use vue debounce via CDN like so: (It is recommended that you don't use @latest however)

<script src="https://unpkg.com/vue-debounce@latest/dist/vue-debounce.min.js">
<script>
  vueDebounce.vueDebounce({ lock: true })
</script>

Setup

With vue3 we simply need to import the new directive function vueDebounce this function takes in an object of options (found above)

Using vue-debounce Globally:

import vueDebounce from 'vue-debounce'
import { createApp } from 'vue';
import App from './App.vue';

const app = createApp(App)
app
  .directive('debounce', vueDebounce({ lock: true }))
  .mount('#app');

Using the setup API at the component level:

<script setup>
import vueDebounce from 'vue-debounce'

const vDebounce = vueDebounce({ lock: true })
</script>

Using vue-debounce at a component level using the option API:

import vueDebounce from 'vue-debounce'

export default {
  directives: {
    debounce: vueDebounce({ lock: true })
  }
}

Using Just Debounce

With Vue-debounce you're also able to just use the debouncing function.

Simply require the debounce file.

import { debounce } from 'vue-debounce'

The debounce function returns a function back which in turn is debounced, so you can set them up ahead of time:

const dFn = debounce(val => console.log('normal format', val), '400ms')

dFn(10) // => 'normal format' 10
// Or
debounce(val => console.log('just a number!'), 400)(10) // => 'just a number!' 10

Usage

Then attach a time:format to the directive, and set the value to the function you want to call and attach it to your input element

Example:

<input v-debounce:300ms="myFunc" type="text" />

If no wait timer is passed in, then the directive will default to whatever you set defaultTime to, OR 300ms if that isn't set.

You can pass the time in multiple formats:

<!-- If no time format is attached ms is used -->
<input v-debounce:300="myFunc" type="text" />

<!-- Seconds format is supported -->
<input v-debounce:1s="myFunc" type="text" />

The value of the input is passed along to your function as the first parameter, and the 2nd parameter is the event object itself.

Modifier Usage

Using modifiers works just like normal Vue directives. You can chain them to the timeout value and each other. Some examples include:

IMPORTANT NOTE: Modifiers WILL overwrite options you have set, for example if you set the fireOnEmpty option set to true and then tag a input with the cancelonempty modifier then the debounced function will cancel when THAT input is empty instead of fire.

<!-- Using Modifiers locking the input so the enter key isn't registered -->
<input v-debounce:1s.lock="myFunc" type="text" />

<!-- Using Modifiers unlocking the input so the enter key is registered -->
<!-- If you've set lock to true as an option when adding this module -->
<input v-debounce:1s.unlock="myFunc" type="text" />

<!-- Using the fireonempty modifier triggers your debounced function when this specific input field is empty -->
<input v-debounce:1s.fireonempty="myFunc" type="text" />

<!-- Using the cancelonempty modifier tells debounce to cancel function execution when the field is empty -->
<input v-debounce:1s.cancelonempty="myFunc" type="text" />

Overwriting Events

As of Version 1.2.0 you can assign specific event listeners to specific inputs. Doing so overwrites ANY of the listed events set with listenTo

Example:

// This can accept an array or a single string when using the bind `:` syntax
<input v-debounce:1s="myFunc" :debounce-events="['click', 'keydown']">
<input v-debounce:1s="myFunc" :debounce-events="'click'">

// You can also just use it as an attribute, though if passing multiple events binding it is preferred
<input v-debounce:1s="myfunc" debounce-events="click">

A full example:

<template>
  <input v-debounce:400ms="myFn" type="text" />
  <input v-debounce:400ms="myFn" debounce-events="click" type="text" />
</template>
<script>
export default {
  methods: {
    myFn(val, e) {
      console.log(val) // => The value of the input
      console.log(e) // => The event object
    }
  }
}
</script>

Typescript Support

While this project is not written in typescript, we do define types in the types directory. Unfortunately the way Vue is currently typed the only type support you will get is when you Vue.use(vueDebounce).

i.e.

import Vue from 'vue'
import vueDebounce, { PluginConfig, debounce } from 'vue-debounce'

debounce(() => console.log('just a number!'), 400)
debounce(() => console.log('normal format'), '400ms')

Vue.use<PluginConfig>(vueDebounce, { lock: true, defaultTime: '400ms', listenTo: 'keyup' })

Hopefully in the future Vue will allow directives to type the modifiers and values that are accepted.

Caveats

If a library you are using such as Vueftify is already using a specified event, it will block vue debounce from being able to listen to that event.

As of v3.1.0 I have significantly improved compatability with these kinds of libraries, however this problem still remains.

For example, Vuetify makes pretty heavy use of the onblur event for a lot of it's styles/animatons, so I'd recommend telling vue-debounce to listen for focusout instead, if you want debounce to trigger on a blur like event.

I will keep doing research into a better way to solve this little issue, but for now the improved compatability should help a lot!