Vue-lazily NPM

The easiest way to lazy load your content.

Inspired by vue-promised, recommend to look at it if you need loading/errors handling without lazy loading.

Demo

Features

⚔️ Works for both Vue 3 and 2
👁️ Loads content when it becomes visible
📝 Manipulate data directly in the template
📍 Slots for loading and error states
No dependencies.

Starting from v2 The minimum supported Vue version - 2.7. If you use older version of Vue, please install previous version of this library - ^1.0.0.

Why does this library exist?

Usually, on big pages, rendering all content at once can cause performance problems with big "Time to Interactive" or "Largest Contentful Paint" time, or even bigger problem if SSR used - server should render all the content before user could see the page.

And in most cases, the user will not even scroll to that content, but must wait to it to be rendered.

VueLazily solves these problems by loading data only when it becomes visible and handle loading/error state itself using slots 🙂.

Installation

yarn add vue-lazily

npm i vue-lazily

Usage

Global

// Vue 2

import Vue from 'vue'
import VueLazily from 'vue-lazily'

Vue.use(VueLazily, { /* options */ })


// Vue 3

import { createApp } from 'vue'
import VueLazily from 'vue-lazily'

const app = createApp(App)
app.use(VueLazily, { /* options */ }))

Local

<script>
import { Lazily } from 'vue-lazily'

export default {
  components: {
    Lazily
  }
}
</script>

Basic Example

Using url string:

<template>
  <Lazily
    action="https://rickandmortyapi.com/api/character/1"
    #default="{ data: { image, name, species } }"
  >
    <img :src="image" :alt="name" />
    <h2>{{ name }}</h2>
    <span>{{ species }}</span>
  </Lazily>
</template>

Using component's method:

<template>
  <Lazily :action="getCharacter" #default="{ data: { image, name, species } }">
    <img :src="image" :alt="name" />
    <h2>{{ name }}</h2>
    <span>{{ species }}</span>
  </Lazily>
</template>

<script>
export default {
  methods: {
    getCharacter() {
      return fetch('https://rickandmortyapi.com/api/character/1').then(res =>
        res.json()
      )
    }
  }
}
</script>

Using slots:

<template>
  <Lazily action="https://rickandmortyapi.com/api/character/1">
    <template #pending>Loading...</template>
    <template #error="{ error }">{{ error.message }}</template>
    <template #default="{ data: { image, name, species } }">
      <img :src="image" :alt="name" />
      <h2>{{ name }}</h2>
      <span>{{ species }}</span>
    </template>
  </Lazily>
</template>

API Reference

options

Name	Description	Type
`name`	Component name. Defaults to `Lazily`	`String`
`props`	Props which will be passed to component	`Object`

props

All of these props could be passed to global config as well as directly to component.

Name	Description	Type
`action`	Url string, method or promise for default action handler. Or anything else that could be passed to custom `actionHandler`	`any`
`lazy`	Enables lazy loading which uses Intersection Observer API under the hood. Defaults to `true`	`Boolean`
`delay`	Delay in ms to wait before displaying the pending slot. Disabled by default, if passed `true` - defaults to `200`. If disabled - pending slot will be rendered in SSR	`Boolean` `Number`
`margin`	`rootMargin` option for IntersectionObserver class. Defaults to `0px`. See docs	`String`
`threshold`	`threshold` option for IntersectionObserver class. Defaults to `0`. See docs	`String`
`height`	Height of an element that is shown before pending slot. Defaults to `0px`	`String`
`watch`	Reactive value or watch function to watch changes and rerun action	`Number` `String` `Array` `Object` `Function`
`actionHandler`	Custom action handler. F.e. to use custom `fetch`, `axios` or `apollo`. Gets action prop as argument	`Function`

slots

All slots can be used as scoped or regular slots.

Name	Description	Scope
`pending`	Content to display while the action is pending and before delay is over	previously resolved `data`, `observed` flag
default	Content to display once the action has been successfully resolved	resolved `data`
`error`	Content to display if the action is rejected	throwed `error`
`combined`	Combines all slots to provide a granular control over what should be displayed	`context` object