“热重载”不只是当修改文件的时候简单重新加载页面。启用热重载后，当你修改 .vue 文件时，该组件的所有实例将在不刷新页面的情况下被替换。它甚至保持了应用程序和被替换组件的当前状态！当你调整模版或者修改样式时，这极大地提高了开发体验。
1. 热重载——状态保留规则
- 当编辑一个组件的
<template>时，这个组件实例将就地重新渲染，并保留当前所有的私有状态。能够做到这一点是因为模板被编译成了新的无副作用的渲染函数。 - 当编辑一个组件的
<script>时，这个组件实例将就地销毁并重新创建。(应用中其它组件的状态将会被保留) 是因为<script>可能包含带有副作用的生命周期钩子，所以将重新渲染替换为重新加载是必须的，这样做可以确保组件行为的一致性。这也意味着，如果你的组件带有全局副作用，则整个页面将会被重新加载。 <style>会通过vue-style-loader自行热重载，所以它不会影响应用的状态。
2. 热重载用法
当使用脚手架工具 vue-cli 时，热重载是开箱即用的。
当手动设置工程时，热重载会在你启动 webpack-dev-server --hot 服务时自动开启。
继续查阅 vue-loader 内部使用的 vue-hot-reload-api。
3. 关闭热重载
热重载默认是开启的，除非遇到以下情况：
- webpack 的
target的值是node(服务端渲染) - webpack 会压缩代码
process.env.NODE_ENV === 'production'
可以设置 hotReload: false 选项来显式地关闭热重载：
module: {
rules: [
{
test: /.vue$/,
loader: 'vue-loader',
options: {
hotReload: false // 关闭热重载
}
}
]
}
4. ESLint
官方的 eslint-plugin-vue 同时支持在 Vue 单文件组件的模板和脚本部分的代码校验。
请确认在ESLint 配置文件中使用该插件要导入的配置：
// .eslintrc.js
module.exports = {
extends: [
"plugin:vue/essential"
]
}
// .eslintrc.js
module.exports = {
root: true,
parserOptions: {
parser: "babel-eslint",
sourceType: "module"
},
env: {
browser: true,
node: true,
es6: true
},
extends: ["plugin:vue/recommended", "eslint:recommended"],
// add your custom rules here
// it is base on https://github.com/vuejs/eslint-config-vue
rules: {
"vue/html-self-closing": 0,
"vue/max-attributes-per-line": [
2,
{
singleline: 20,
multiline: {
max: 1,
allowFirstLine: false
}
}
],
"vue/multiline-html-element-content-newline": "off",
"vue/name-property-casing": [2, "PascalCase"],
"vue/no-v-html": "off",
"vue/singleline-html-element-content-newline": "off",
"accessor-pairs": 2,
"vue/attribute-hyphenation": 0,
"array-bracket-spacing": [2, "never"],
"arrow-spacing": [
2,
{
before: true,
after: true
}
],
"block-spacing": [2, "always"],
"brace-style": [
2,
"1tbs",
{
allowSingleLine: true
}
],
camelcase: [
0,
{
properties: "always"
}
],
"comma-dangle": [2, "never"],
"comma-spacing": [
2,
{
before: false,
after: true
}
],
"comma-style": [2, "last"],
"constructor-super": 2,
curly: [2, "multi-line"],
"dot-location": [2, "property"],
"eol-last": 2,
eqeqeq: 0,
"generator-star-spacing": [
2,
{
before: true,
after: true
}
],
"handle-callback-err": [2, "^(err|error)$"],
indent: [
2,
2,
{
SwitchCase: 1
}
],
"jsx-quotes": [2, "prefer-single"],
"key-spacing": [
2,
{
beforeColon: false,
afterColon: true
}
],
"keyword-spacing": [
2,
{
before: true,
after: true
}
],
"new-cap": [
2,
{
newIsCap: true,
capIsNew: false
}
],
"new-parens": 2,
"no-array-constructor": 2,
"no-caller": 2,
"no-console": "off",
"no-class-assign": 2,
"no-cond-assign": 2,
"no-const-assign": 2,
"no-control-regex": 0,
"no-debugger": process.env.NODE_ENV === "production" ? 2 : 0,
"no-delete-var": 2,
"no-dupe-args": 2,
"no-dupe-class-members": 2,
"no-dupe-keys": 2,
"no-duplicate-case": 2,
"no-empty-character-class": 2,
"no-empty-pattern": 2,
"no-eval": 2,
"no-ex-assign": 2,
"no-extend-native": 2,
"no-extra-bind": 2,
"no-extra-boolean-cast": 2,
"no-extra-parens": [2, "functions"],
"no-fallthrough": 2,
"no-floating-decimal": 2,
"no-func-assign": 2,
"no-implied-eval": 2,
"no-inner-declarations": [2, "functions"],
"no-invalid-regexp": 2,
"no-irregular-whitespace": 2,
"no-iterator": 2,
"no-label-var": 2,
"no-labels": [
2,
{
allowLoop: false,
allowSwitch: false
}
],
"no-lone-blocks": 2,
"no-mixed-spaces-and-tabs": 2,
"no-multi-spaces": 2,
"no-multi-str": 2,
"no-multiple-empty-lines": [
2,
{
max: 1
}
],
"no-native-reassign": 2,
"no-negated-in-lhs": 2,
"no-new-object": 2,
"no-new-require": 2,
"no-new-symbol": 2,
"no-new-wrappers": 2,
"no-obj-calls": 2,
"no-octal": 2,
"no-octal-escape": 2,
"no-path-concat": 2,
"no-proto": 2,
"no-redeclare": 2,
"no-regex-spaces": 2,
"no-return-assign": [2, "except-parens"],
"no-self-assign": 2,
"no-self-compare": 2,
"no-sequences": 2,
"no-shadow-restricted-names": 2,
"no-spaced-func": 2,
"no-sparse-arrays": 2,
"no-this-before-super": 2,
"no-throw-literal": 2,
"no-trailing-spaces": 2,
"no-undef": 2,
"no-undef-init": 2,
"no-unexpected-multiline": 2,
"no-unmodified-loop-condition": 2,
"no-unneeded-ternary": [
2,
{
defaultAssignment: false
}
],
"no-unreachable": 2,
"no-unsafe-finally": 2,
"no-unused-vars": [
1,
{
vars: "all",
args: "none"
}
],
"no-useless-call": 2,
"no-useless-computed-key": 2,
"no-useless-constructor": 2,
"no-useless-escape": 0,
"no-whitespace-before-property": 2,
"no-with": 2,
"object-curly-spacing": [2, "always"],
"one-var": [
2,
{
initialized: "never"
}
],
"operator-linebreak": [
2,
"after",
{
overrides: {
"?": "before",
":": "before"
}
}
],
"padded-blocks": [2, "never"],
"prefer-const": 2,
quotes: [
2,
"double",
{
avoidEscape: true,
allowTemplateLiterals: true
}
],
semi: [2, "always"],
"semi-spacing": [
2,
{
before: false,
after: true
}
],
"space-before-blocks": [2, "always"],
"space-in-parens": [2, "never"],
"space-infix-ops": 2,
"space-unary-ops": [
2,
{
words: true,
nonwords: false
}
],
"spaced-comment": [
2,
"always",
{
markers: ["global", "globals", "eslint", "eslint-disable", "*package", "!", ","]
}
],
"template-curly-spacing": [2, "never"],
"use-isnan": 2,
"valid-typeof": 2,
"wrap-iife": [2, "any"],
"yield-star-spacing": [2, "both"],
yoda: [2, "never"]
}
};
接下来从命令行运行：
eslint --ext js,vue MyComponent.vue
另一个选项是使用 eslint-loader, 那么你的 *.vue 文件在开发过程中每次保存的时候就会自动进行代码校验：
npm install -D eslint eslint-loader
请确保它是作为一个 pre-loader 运用的：
// webpack.config.js
module.exports = {
// ... 其它选项
module: {
rules: [
{
enforce: 'pre',
test: /.(js|vue)$/,
loader: 'eslint-loader',
exclude: /node_modules/
}
]
}
}
4. stylelint
stylelint 支持在 Vue 单文件组件的样式部分的代码校验。
接下来从命令行运行：
stylelint MyComponent.vue
另一个选项是使用 stylelint-webpack-plugin:
npm install -D stylelint-webpack-plugin
请确保它是作为一个插件运用的：
// webpack.config.js
const StyleLintPlugin = require('stylelint-webpack-plugin');
module.exports = {
// ... 其它选项
plugins: [
new StyleLintPlugin({
files: ['**/*.{vue,htm,html,css,sss,less,scss,sass}'],
})
]
}
