React.js和Vue.js的语法并列比较
React.js和Vue.js都是很好的框架。而且Next.js和Nuxt.js甚至将它们带入了一个新的高度,这有助于我们以更少的配置和更好的可维护性来创建应用程序。但是,如果你必须经常在框架之间切换,在深入探讨另一个框架之后,你可能会轻易忘记另一个框架中的语法。在本文中,我总结了这些框架的基本语法和方案,然后并排列出。我希望这可以帮助我们尽快掌握语法,不过限于篇幅,这篇文章只比较React.js和Vue.js,下一篇再谈Next.js个Nuxt.js。
Github
https://github.com/oahehc/react-vue-comparison
Render
React.js
ReactDOM.render(<App />, document.getElementById("root"));
Vue.js
new Vue({
  render: (h) => h(App),
}).$mount("#root");
基本组件
React.js
Class component
class MyReactComponent extends React.Component {
  render() {
    return <h1>Hello world</h1>;
  }
}
Function component
function MyReactComponent() {
  return <h1>Hello world</h1>;
}
Vue.js
<template>
  <h1>Hello World</h1>
</template>
<script>
 export default {
 name: "MyVueComponent",
 };
</script> 
 
Prop
React.js
function MyReactComponent(props) {
  const { name, mark } = props;
  return <h1>Hello {name}{mark}</h1>;
}
MyReactComponent.propTypes = {
  name: PropTypes.string.isRequired,
  mark: PropTypes.string,
}
MyReactComponent.defaultProps = {
  mark: '!',
}
...
<MyReactComponent name="world">
Vue.js
<template>
  <h1>Hello {{ name }}</h1>
</template>
<script>
 export default {
 name: "MyVueComponent",
 props: {
 name: {
 type: String,
 required: true,
 },
 mark: {
 type: String,
 default: "!",
 },
 },
 };
</script>
...
<MyVueComponent name="World" />
事件绑定
React.js
Class component
class MyReactComponent extends React.Component {
  save = () => {
    console.log("save");
  };
  render() {
    return <button onClick={this.save}>Save</button>;
  }
}
Function component
function MyReactComponent() {
  const save = () => {
    console.log("save");
  };
  return <button onClick={save}>Save</button>;
}
Vue.js
<template>
  <button @click="save()">Save</button>
</template>
<script>
 export default {
 methods: {
 save() {
 console.log("save");
 },
 },
 };
</script>
自定义事件
React.js
function MyItem({ item, handleDelete }) {
  return <button onClick={() => handleDelete(item)}>{item.name}</button>;
  /*
 * 应用useCallback钩子来防止在每次渲染时生成新的函数。
 *
 * const handleClick = useCallback(() => handleDelete(item), [item, handleDelete]);
 *
 * return <button onClick={handleClick}>{item.name}</button>;
 */
}
...
function App() {
  const handleDelete = () => { ... }
  return <MyItem item={...} handleDelete={handleDelete} />
}
Vue.js
<template>
  <button @click="deleteItem()">{{item.name}}</button>
</template>
<script>
 export default {
 name: "my-item",
 props: {
 item: Object,
 },
 methods: {
 deleteItem() {
 this.$emit("delete", this.item);
 },
 },
 };
</script>
...
<template>
  <MyItem :item="item" @delete="handleDelete" />
</template>
<script>
 export default {
 components: {
 MyItem,
 },
 methods: {
 handleDelete(item) { ... }
 },
 };
</script>
State
React.js
Class component
class MyReactComponent extends React.Component {
  state = {
    name: 'world,
 }
 render() {
 return <h1>Hello { this.state.name }</h1>;
 }
}
Function component
function MyReactComponent() {
  const [name, setName] = useState("world");
  return <h1>Hello {name}</h1>;
}
Vue.js
<template>
  <h1>Hello {{ name }}</h1>
  <!-- 使用组件状态作为prop -->
  <my-vue-component :name="name">
</template>
<script>
 export default {
 data() {
 return { name: "world" };
 },
 };
</script>
Change-State
React.js
Class component
class MyReactComponent extends React.Component {
  state = {
    count: 0,
  };
  increaseCount = () => {
    this.setState({ count: this.state.count + 1 });
    // 在更新之前获取当前状态,以确保我们没有使用陈旧的值
    // this.setState(currentState => ({ count: currentState.count + 1 }));
  };
  render() {
    return (
      <div>
 <span>{this.state.count}</span>
 <button onClick={this.increaseCount}>Add</button>
 </div>
    );
  }
}
Function component
function MyReactComponent() {
  const [count, setCount] = useState(0);
  const increaseCount = () => {
    setCount(count + 1);
    // setCount(currentCount => currentCount + 1);
  };
  return (
    <div>
 <span>{count}</span>
 <button onClick={increaseCount}>Add</button>
 </div>
  );
}
Vue.js
<template>
  <div>
    <span>{{count}}</span>
    <button @click="increaseCount()">Add</button>
  </div>
</template>
<script>
 export default {
 data() {
 return { count: 0 };
 },
 methods: {
 increaseCount() {
 this.count = this.count + 1;
 },
 },
 };
</script>
双向绑定 (仅Vue.js)
React.js
React没有双向绑定,因此我们需要自己处理数据流
function MyReactComponent() {
  const [content, setContent] = useState("");
  return (
    <input
 type="text"
 value={content}
 onChange={(e) => setContent(e.target.value)}
 />
  );
}
Vue.js
<template>
  <input type="text" v-model="content" />
</template>
<script>
 export default {
 data() {
 return { content: "" };
 },
 };
</script>
计算属性
React.js
React.js没有计算属性,但我们可以通过react hook轻松实现
function DisplayName({ firstName, lastName }) {
  const displayName = useMemo(() => {
    return `${firstName} ${lastName}`;
  }, [firstName, lastName]);
  return <div>{displayName}</div>;
}
...
<DisplayName firstName="Hello" lastName="World" />
Vue.js
<template>
  <div>{{displayName}}</div>
</template>
<script>
 export default {
 name: "display-name",
 props: {
 firstName: String,
 lastName: String,
 },
 computed: {
 displayName: function () {
 return `${this.firstName} ${this.lastName}`;
 },
 },
 };
</script>
...
<DisplayName firstName="Hello" lastName="World" />
Watch
React.js
React.js没有 watch 属性,但是我们可以通过react hook轻松实现
function MyReactComponent() {
  const [count, setCount] = useState(0);
  const increaseCount = () => {
    setCount((currentCount) => currentCount + 1);
  };
  useEffect(() => {
    localStorage.setItem("my_count", newCount);
  }, [count]);
  return (
    <div>
 <span>{count}</span>
 <button onClick={increaseCount}>Add</button>
 </div>
  );
}
Vue.js
<template>
  <div>
    <span>{{count}}</span>
    <button @click="increaseCount()">Add</button>
  </div>
</template>
<script>
 export default {
 data() {
 return { count: 0 };
 },
 methods: {
 increaseCount() {
 this.count = this.count + 1;
 },
 },
 watch: {
 count: function (newCount, oldCount) {
 localStorage.setItem("my_count", newCount);
 },
 },
 };
</script>
Children-and-Slot
React.js
function MyReactComponent({ children }) {
  return <div>{children}</div>;
}
...
<MyReactComponent>Hello World</MyReactComponent>
Vue.js
<template>
  <div>
    <slot />
  </div>
</template>
<script>
 export default {
 name: "my-vue-component",
 };
</script>
...
<MyVueComponent>Hello World</MyVueComponent>
渲染HTML
React.js
function MyReactComponent() {
  return <div dangerouslySetInnerHTML={{ __html: "<pre>...</pre>" }} />;
}
Vue.js
<template>
  <div v-html="html"></div>
</template>
<script>
 export default {
 data() {
 return {
 html: "<pre>...</pre>",
 };
 },
 };
</script>
条件渲染
React.js
function MyReactComponent() {
  const [isLoading, setLoading] = useState(true);
  return (
    <div>
 {isLoading && <span>Loading...</span>}
 {isLoading ? <div>is loading</div> : <div>is loaded</div>}
 </div>
  );
}
Vue.js
<template>
  <div>
    <!--v-show: 总是渲染,但根据条件更改CSS-->
    <span v-show="loading">Loading...</span>
    <div>
      <div v-if="loading">is loading</div>
      <div v-else>is loaded</div>
    </div>
  </div>
</template>
<script>
 export default {
 data() {
 return { loading: true };
 },
 };
</script>
列表渲染
React.js
function MyReactComponent({ items }) {
  return (
    <ul>
 {items.map((item) => (
 <li key={item.id}>
 {item.name}: {item.desc}
 </li>
 ))}
 </ul>
  );
}
Vue.js
<template>
  <ul>
    <li v-for="item in items" :key="item.id">
      {{item.name}}: {{item.desc}}
    </li>
  </ul>
</template>
<script>
 export default {
 props: {
 items: Array,
 },
 };
</script> 
 
Render-Props
React.js
function Modal({children, isOpen}) {
  const [isModalOpen, toggleModalOpen] = useState(isOpen);
  return (
    <div className={isModalOpen ? 'open' : 'close'}>
 {type children === 'function' ? children(toggleModalOpen) : children}
 </div>)
  ;
}
Modal.propTypes = {
  isOpen: PropTypes.bool,
  children: PropTypes.oneOfType([PropTypes.string, PropTypes.element]).isRequired,
}
Modal.defaultProps = {
  isOpen: false,
}
...
<Modal isOpen>
  {(toggleModalOpen) => {
    <div>
      <div>...</div>
      <button onClick={() => toggleModalOpen(false)}>Cancel</button>
    </div>
 }}
</Modal>
Vue.js(slot)
<template>
  <div v-show="isModalOpen">
    <slot v-bind:toggleModal="toggleModalOpen" />
  </div>
</template>
<script>
 export default {
 name: "modal",
 props: {
 isOpen: {
 type: Boolean,
 default: false,
 },
 },
 data() {
 return {
 isModalOpen: this.isOpen,
 };
 },
 methods: {
 toggleModalOpen(state) {
 this.isModalOpen = state;
 },
 },
 };
</script>
...
<Modal isOpen>
  <template v-slot="slotProps">
    <div>...</div>
    <button @click="slotProps.toggleModal(false)">Close</button>
  </template>
</Modal>
生命周期
React.js
Class component
class MyReactComponent extends React.Component {
  static getDerivedStateFromProps(props, state) {}
  componentDidMount() {}
  shouldComponentUpdate(nextProps, nextState) {}
  getSnapshotBeforeUpdate(prevProps, prevState) {}
  componentDidUpdate(prevProps, prevState) {}
  componentWillUnmount() {}
  render() {
    return <div>Hello World</div>;
  }
}
Function component
function MyReactComponent() {
  // componentDidMount
  useEffect(() => {}, []);
  // componentDidUpdate + componentDidMount
  useEffect(() => {});
  // componentWillUnmount
  useEffect(() => {
    return () => {...}
  }, []);
  // 在渲染之后但在屏幕更新之前同步运行
  useLayoutEffect(() => {}, []);
  return <div>Hello World</div>;
}
Vue.js
<template>
  <div>Hello World</div>
</template>
<script>
 export default {
 beforeCreate() {},
 created() {},
 beforeMount() {},
 mounted() {},
 beforeUpdate() {},
 updated() {},
 beforeDestroy() {},
 destroyed() {},
 };
</script>
错误处理
React.js
class ErrorBoundary extends React.Component {
  state = { hasError: false };
  static getDerivedStateFromError(error) {
    // 更新状态,这样下一个渲染将显示回退UI。
    return { hasError: true };
  }
  componentDidCatch(error, errorInfo) {}
  render() {
    if (this.state.hasError) return <h1>Something went wrong.</h1>;
    return this.props.children;
  }
}
...
<ErrorBoundary>
  <App />
</ErrorBoundary>
Vue.js
const vm = new Vue({
  data: {
    error: "",
  },
  errorCaptured: function(err, component, details) {
    error = err.toString();
  }
}
Ref
React.js
Class component
class AutofocusInput extends React.Component {
  constructor(props) {
    super(props);
    this.ref = React.createRef();
  }
  state = {
    content: "",
  };
  componentDidMount() {
    this.ref.current.focus();
  }
  setContent = (e) => {
    this.setState({ content: e.target.value });
  };
  render() {
    return (
      <input
 ref={this.ref}
 type="text"
 value={this.state.content}
 onChange={this.setContent}
 />
    );
  }
}
Function component
function AutofocusInput() {
  const [content, setContent] = useState("");
  const ref = useRef(null);
  useEffect(() => {
    if (ref && ref.current) {
      ref.current.focus();
    }
  }, []);
  return (
    <input
 ref={ref}
 type="text"
 value={content}
 onChange={(e) => setContent(e.target.value)}
 />
  );
}
Vue.js
<template>
  <input ref="input" type="text" v-model="content" />
</template>
<script>
 export default {
 name: "autofocus-input",
 data() {
 return { content: "" };
 },
 mounted() {
 this.$refs.input.focus();
 },
 };
</script>
性能优化
React.js
PureComponent
class MyReactComponent extends React.PureComponent {
  ...
}
shouldComponentUpdate
class MyReactComponent extends React.Component {
  shouldComponentUpdate(nextProps) {...}
  ...
}
React.memo
export default React.memo(
  MyReactComponent,
  (prevProps, nextProps) => {
    ...
  }
);
useMemo
export default function MyReactComponent() {
  return React.useMemo(() => {
    return <div>...</div>;
  }, []);
}
useCallback
function MyItem({ item, handleDelete }) {
  const handleClick = useCallback(() => handleDelete(item), [
    item,
    handleDelete,
  ]);
  return <button onClick={handleClick}>{item.name}</button>;
}
Vue.js
v:once
<span v-once>This will never change: {{msg}}</span>
函数式组件:我们可以将组件标记为 functional,这意味它无状态 (没有响应式数据),也没有实例 (没有 this 上下文)。
<template functional>
  <h1>Hello {{ name }}</h1>
</template>
<script>
 export default {
 name: "MyVueComponent",
 props: {
 name: String,
 },
 };
</script>
keep-alive 组件
<keep-alive>
  <component :is="view"></component>
</keep-alive>
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