vue-debounce

A simple to use directive for debounce solutions

It attaches itself to an event for actions

Content

Features
Installation
Modifiers
Options
Option Defaults
getDirective Usage
Usage
Modifier Usage
Overwriting Events
Use Just Debounce
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
}

getDirective Usage

As of v3.0.0 a new function called getDirective is now exported, this allows you to import a function that lets you create the debounce directive at any level in your app instead of just globally.

Arguments

This function takes in 2 arguments, they are:

version : String - This is the version of vue you're using, simply put '2' or '3' here
- Version automatically defaults to version 2
- This is so that backwards compatibility can still be supported, since I don't have access to the Vue context when you don't install globally
opts : Object - This is the options object, use it the same way you would use it if using vue-debounce globally

import { getDirective } from 'vue-debounce'

const component = {
  directives: {
    // Please see above for arguments you can pass to this function
    debounce: getDirective()
  }
}

// If you are using vue 3 you MUST tell the function this by passing in the first argument
const component = {
  directives: {
    // Pass in 3 to tell the function you're using vue 3, I'm going to work on improving this in the future
    debounce: getDirective(3)
  }
}

Usage

First make sure we tell vue to use it

import Vue from 'vue'
import vueDebounce from 'vue-debounce'

Vue.use(vueDebounce)

// Or if you want to pass in the lock option
Vue.use(vueDebounce, {
  lock: true
})

// Setting a different event to listen to
Vue.use(vueDebounce, {
  listenTo: 'input'
})

// Listening to multiple events
Vue.use(vueDebounce, {
  listenTo: ['input', 'keyup']
})

// Setting a default timer This is set to '300ms' if not specified
Vue.use(vueDebounce, {
  defaultTime: '700ms'
})

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>

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, or just double call the function like so:

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

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

There is a caveat explained in issue #36 which states you're unable to intercept manually triggered events automatically and instead have to trigger the debounced function at the catching point.

For example, if you have a custom component that is manually firing an input event back to the parent, you might do something like this:

<CustomComponent
  v-model="options"
  @input="debouncedSelectUpdate"
/>

Where debounceSelectedUpdate looks like this:

debounceSelectedUpdate () {
  return debounce(() => {
    // Taken from issue #36 as an example
    this.refreshDefaultSelect()
  }, 300)
}

Or have a method that handles it for you and calls debounce etc. If anyone has advice on handling manual vue events automatically please don't hesitate to share!

HudsonMCynner/vue-debounce