JavaScript 語法變化

• 保留字: promise.catch(function() { });

• Arrow functions: <C onPress={() => this.setState({pressed: true})}
• Block scoping: let greeting = 'hi';
• Call spread: Math.max(...array);
• Classes: class C extends React.Component { render() { return <View />; } }
• Constants: const answer = 42;
• Destructuring: var {isActive, style} = this.props;
• for...of: for (var num of [1, 2, 3]) {}
• Modules: import React, { Component } from 'react';
• Computed Properties: var key = 'abc'; var obj = {[key]: 10};
• Object Concise Method: var obj = { method() { return 10; } };
• Object Short Notation: var name = 'vjeux'; var obj = { name };
• Rest Params: function(type, ...args) { }
• Template Literals: var who = 'world'; var str = `Hello ${who}`;

• Function Trailing Comma: function f(a, b, c,) { }
• Async Functions: async function doStuffAsync() { const foo = await doOtherStuffAsync(); };

• Object Spread: var extended = { ...obj, a: 10 };

• JSX: <View style={{color: 'red'}} />
• Flow: function foo(x: ?number): string {}

Polyfills

• console.{log, warn, error, info, trace, table, group, groupEnd}
• CommonJS require
• XMLHttpRequest, fetch
• {set, clear}{Timeout, Interval, Immediate}, {request, cancel}AnimationFrame
• navigator.geolocation

• Object.assign
• String.prototype.{startsWith, endsWith, repeat, includes}
• Array.from
• Array.prototype.{find, findIndex}

• Array.prototype.{includes}

• Object.{entries, values}

• __DEV__