UniApp is a development tool based on the Vue.js framework, which can compile a set of codes into multiple platform applications at the same time, such as WeChat applets, H5 pages, Apps, etc. In UniApp, we can customize filters and perform data processing to achieve more flexible and efficient development.
A filter is a function that converts and processes data formats. Common application scenarios include date formatting, data thousandth separation, price formatting, etc. In UniApp, filters are created using the filter method provided by the Vue.js framework.
The principle of the filter is very simple. It will receive an input value, followed by the pipe operator |
, followed by the name of the filter, and then convert the input value to the output value. For example:
{{ inputValue | filterName }}
In the UniApp project, we can create a filters
folder in the common
directory , and then create an index.js
file to define all filters. Suppose we need to implement a time formatting filter, we can follow the following steps:
First, in the index.js
file, introduce Vue.js:
import Vue from 'vue'
Then, create a filter named formatDate
:
Vue.filter('formatDate', function (value, format) { // 根据format参数进行格式化处理 // ... return formattedValue })
Finally, export the Vue instance:
export default Vue
In the page, we can use custom filters through the |
pipeline operator. For example, if we want to format the timestamp into the form of "yyyy-MM-dd hh:mm:ss", we can follow the following steps:
First, introduce a custom filter:
import Vue from '@/common/filters'
Then, call where the filter needs to be used:
<template> <view> <text>{{ timestamp | formatDate('yyyy-MM-dd hh:mm:ss') }}</text> </view> </template>
Data Processing refers to processing and processing the data returned by the API so that it can be better displayed and used on the page. In UniApp, data processing can be achieved through the computed attribute of Vue.js.
The principle of data processing is to monitor the specified data changes, then perform corresponding processing and calculations based on the changed data, and return the calculated results. In this way, we can use the processed data directly in the page without maintaining a large amount of logic code.
In the page component of UniApp, we can create calculated properties through the computed
property to achieve data processing and processing. Suppose we need to calculate the discount price of the product price, we can follow the following steps:
First, define the original price and discount of the product in the data
attribute of the page:
data() { return { originalPrice: 100.00, discount: 0.8 } }
Then, create a calculated attribute named discountPrice
:
computed: { discountPrice() { return this.originalPrice * this.discount } }
Finally, use the calculated attribute in the page:
<template> <view> <text>商品价格:{{ originalPrice }}</text> <text>折扣价:{{ discountPrice }}</text> </view> </template>
If you need to perform some specific operations when the data changes, you can monitor the data changes through the watch
attribute. Suppose we need to pop up a prompt box when the price of the product changes. We can follow the following steps:
First, define the price of the product in the data
attribute of the page:
data() { return { price: 100.00 } }
Then, create a listener named price
:
watch: { price(newPrice, oldPrice) { uni.showToast({ title: `商品价格变化:${oldPrice} -> ${newPrice}`, icon: 'none' }) } }
Finally, use the price input box on the page and bind the v-model
command:
<template> <view> <input v-model="price" type="number" placeholder="请输入商品价格" /> </view> </template>
The following is a complete sample code that demonstrates how to implement custom filters and data processing in UniApp:
// common/filters/index.js import Vue from 'vue' Vue.filter('formatDate', function (value, format) { // 根据format参数进行格式化处理 // ... return formattedValue }) export default Vue
// pages/home/index.vue <template> <view> <text>{{ timestamp | formatDate('yyyy-MM-dd hh:mm:ss') }}</text> <input v-model="price" type="number" placeholder="请输入商品价格" /> <text>商品价格:{{ price }}</text> <text>折扣价:{{ discountPrice }}</text> </view> </template> <script> import Vue from '@/common/filters' export default { data() { return { timestamp: Date.now(), price: 100.00, discount: 0.9 } }, computed: { discountPrice() { return this.price * this.discount } }, watch: { price(newPrice, oldPrice) { uni.showToast({ title: `商品价格变化:${oldPrice} -> ${newPrice}`, icon: 'none' }) } } } </script>
The above is about This introduction to the design and development techniques for implementing custom filters and data processing in UniApp, I hope it will be helpful to everyone in UniApp development. With custom filters and data processing, we can handle data more flexibly and provide a better user experience.
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