# vue-waterfall-easy 2.x
1. This is a vue component that contains waterfall flow layout and infinite scroll loading
2. Compared to other implementations,there is no need to specify the width and height of the image in the returned data
3. It is because of the second item that the image is preloaded and then layout
4. Responsive layout,adapt mobile
5. Simple to use

## [中文文档](https://github.com/lfyfly/vue-waterfall-easy/blob/master/README-CN.md)
## [Demo](https://lfyfly.github.io/vue-waterfall-easy/demo/)
## [code of demo](https://github.com/lfyfly/vue-waterfall-easy/blob/master/src/App.vue)
## [update list](https://github.com/lfyfly/vue-waterfall-easy/issues/8)
## [github](https://github.com/lfyfly/vue-waterfall-easy)

## 1. Usage
### 1.1 Installation

```
npm install vue-waterfall-easy --save
```

### 1.2 es6 import
```js
import vueWaterfallEasy from 'vue-waterfall-easy'
```
```js

export default {
  name: 'app',
  components: {
    vueWaterfallEasy
  }
}
```
### 1.3 scripts import
[download vueWaterfallEasy.js](https://github.com/lfyfly/vue-waterfall-easy/blob/master/src/vue-waterfall-easy/script/vueWaterfallEasy.js)
```html
<script src="path/to/vue/vue.js"></script>
<script src="path/to/vueWaterfallEasy.js"></script>
```
```js
new Vue({
  el: '#app',
  components: {
    vueWaterfallEasy
  }
})
```
### 1.4 Supports require.js and sea.js module import

## 2. Basic example
html
```html
<vue-waterfall-easy :imgsArr="imgsArr" @scrollReachBottom="getData"></vue-waterfall-easy>
```

**If imgArr is a replacement update, the data returned by the getData method new request overwrites the original data.**

**If imgArr is an incremental update, the data returned by the new request of getData method is merged with the original data. At this time, it is not recommended to use the replacement update, which will waste  performance. The following example is an incremental update.**

js

```js
import vueWaterfallEasy from './vue-waterfall-easy/vue-waterfall-easy.vue'
import axios from 'axios'
export default {
  name: 'app',
  data() {
    return {
      imgsArr: [],
      group: 0,// request param
    }
  },
  components: {
    vueWaterfallEasy
  },
  methods: {
    getData() {
      // In the real environment,the backend will return a new image array based on the parameter group.
      // Here I simulate it with a stunned json file.
      axios.get('./static/mock/data.json?group=' + this.group)
        .then(res => {
          this.imgsArr = this.imgsArr.concat(res.data)
          this.group++
        })
    },
  },
  created() {
    this.getData()
  }
}
```
[more detail see App.vue file](https://github.com/lfyfly/vue-waterfall-easy/blob/master/src/App.vue)

## 3. Props
props | type | default | description
---|---|---|---
width | Number |  - | Container width（px）,default is 100% relative parent element width,**Due to the responsiveness,all its parent's width must be 100% relative to the browser window at this time**,See the example after the table<br>**If it is fixed width, you must set the width prop **, not just its parent element set fixed width
height | Number\|String | - | Container height, the default unit `px` for the value of the `Number` type, the unit can be specified when the value is the type of `String`<br>**When you do not specify the `height` value, the default is relative to the height of the parent element 100%, then the parent element must have a height**
gap | Number | 20 | [Pc] space between pictures(px)
mobileGap | Number | 8 | [Mobile] space between pictures(px)
imgsArr | Array | [] | **required**<br>Data used to render the waterfall stream<br>Each array element is an object and must have `src` and `href` attributes.<br>The `src` attribute represents the SRC attribute of the picture<br>The `href` attribute represents the link to click to jump <br>**if your key is not `src` and `href`, you can use the two properties of `srcKey` and `hrefKey` to do the key value replacement.**
srcKey | String | 'src' | When the key value of your picture address is not `src`, you can use this property to replace it.
hrefKey | String | 'href' |  When the key value of your picture address is not `href`, you can use this property to replace it.
imgWidth | Number | 240 | The width of the picture（px）
maxCols | Number | 5 | Waterfall shows the maximum number of columns
linkRange | String | 'card' | Identify click to trigger jump link range<br>value:<br>'card' Whole card range<br> 'img' image range <br> 'custom' Customize the link range through slots
isRouterLink | Boolean | false | Render the a tag when the value is false<br>Render the router-link component when the value is true
reachBottomDistance | Number | 0 | The distance(px) from the bottom of the container when the scrolling triggers the scrollReachBottom event
loadingDotCount | Number | 3 | The number of default loading animation dots
loadingDotStyle | Object | null | The style object of the small dots in the default loading element
loadingTimeOut | Number | 500 |  Preloading events less than 500ms milliseconds do not display loading animations,increasing the user experience
cardAnimationClass | String | 'default-card-animation' | the animation className for the card
enablePullDownEvent | Boolean | false | enable the drop-down event

## 4. Event
event name | description
---|---
scrollReachBottom | When the scroll bar scrolls to the bottom,it is used to trigger a request for new image data
preloaded | Trigger every time image preloading is completed
click | Trigger when the card is clicked,look at an example under the table
imgError | Trigger when img load error
pullDownMove | The mobile terminal takes effect, touches the pull-down event, and the first parameter can obtain the Y-axis moving distance difference, which is often used for pull-down refresh.
pullDownEnd | The mobile terminal takes effect, and the touch pull-down event is raised by the finger, which is often used for pull-down refresh.
click event demo
```html
<vue-waterfall-easy :imgsArr="imgsArr" @scrollReachBottom="getData" @click="clickFn"></vue-waterfall-easy>
```
```js
  clickFn(event, { index, value }) {
    // Prevent a tag jump
    event.preventDefault()
    // Do it only when you click on the image
    if (event.target.tagName.toLowerCase() == 'img') {
      console.log('img clicked',index, value)
    }
  }
```
## 5. methods
### 5.1 waterfallOver
When the rolling load data is over, manual invoking will remove the scroll event.
```
this.$refs.waterfall.waterfallOver()
```
[more detail see App.vue](https://github.com/lfyfly/vue-waterfall-easy/blob/master/src/App.vue)
## 6. slot
### 6.1 default slot
Custom picture description element
#### parameter
parameterpar | description
---|---
props.index | The index of the image in the data array,starting from 0
props.value | The value of imgsArr item

```html
<vue-waterfall-easy :imgsArr="imgsArr" @scrollReachBottom="getData">
  <div class="img-info" slot-scope="props">
    <p class="some-info">picture index: {{props.index}}</p>
    <p class="some-info">{{props.value.info}}</p>
  </div>
</vue-waterfall-easy>
```
### 6.2 slot="loading"
Custom loading element
```html
<div slot="loading" slot-scope="{isFirstLoad}">
  <div slot="loading" v-if="isFirstLoad">first-loading...</div>
  <div v-else="v-else">loading...</div>
</div>
```
### 6.3 slot="waterfall-head"
Waterfall container head slot
```html
<vue-waterfall-easy :imgsArr="imgsArr" @scrollReachBottom="getData">
  <div slot="waterfall-head">waterfall-head</div>
</vue-waterfall-easy>
```
### 6.4 slot="waterfall-over"
when `waterfallOver` method is called，this slot will show
```html
<vue-waterfall-easy :imgsArr="imgsArr" @scrollReachBottom="getData">
  <div slot="waterfall-over">waterfall-over</div>
</vue-waterfall-easy>
```


## 7. Adapted mobile
Don't forget to add following  code in index.html \<head\>
```html
<meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no">
```