如果读者安装的Node.js版本较新，则可以支持大量的JavaScript ES6语法；如果版本太旧并且无法升级，那么该如何检测其是否支持这些新的语法？
这里推荐使用es-checker来检测当前Node.js对ES6的支持情况。使用如下命令安装es-checker:
npm install -g es-checker
安装后，使用命令es-checker检测当前Node.js的版本支持情况，结果如下图：
~ % es-checker
ECMAScript 6 Feature Detection (v1.4.2)
Variables
√ let and const
√ TDZ error for too-early access of let or const declarations
√ Redefinition of const declarations not allowed
√ destructuring assignments/declarations for arrays and objects
√ ... operator
Data Types
√ For...of loop
√ Map, Set, WeakMap, WeakSet
√ Symbol
√ Symbols cannot be implicitly coerced
Number
√ Octal (e.g. 0o1 ) and binary (e.g. 0b10 ) literal forms
√ Old octal literal invalid now (e.g. 01 )
√ Static functions added to Math (e.g. Math.hypot(), Math.acosh(), Math.imul() )
√ Static functions added to Number (Number.isNaN(), Number.isInteger() )
String
√ Methods added to String.prototype (String.prototype.includes(), String.prototype.repeat() )
√ Unicode code-point escape form in string literals (e.g. \u{20BB7} )
√ Unicode code-point escape form in identifier names (e.g. var \u{20BB7} = 42; )
√ Unicode code-point escape form in regular expressions (e.g. var regexp = /\u{20BB7}/u; )
√ y flag for sticky regular expressions (e.g. /b/y )
√ Template String Literals
Function
√ arrow function
√ default function parameter values
√ destructuring for function parameters
√ Inferences for function name property for anonymous functions
× Tail-call optimization for function calls and recursion
Array
√ Methods added to Array.prototype ([].fill(), [].find(), [].findIndex(), [].entries(), [].keys(), [].values() )
√ Static functions added to Array (Array.from(), Array.of() )
√ TypedArrays like Uint8Array, ArrayBuffer, Int8Array(), Int32Array(), Float64Array()
√ Some Array methods (e.g. Int8Array.prototype.slice(), Int8Array.prototype.join(), Int8Array.prototype.forEach() ) added to the TypedArray prototypes
√ Some Array statics (e.g. Uint32Array.from(), Uint32Array.of() ) added to the TypedArray constructors
**Object**
√ __proto__ in object literal definition sets [[Prototype]] link
√ Static functions added to Object (Object.getOwnPropertySymbols(), Object.assign() )
√ Object Literal Computed Property
√ Object Literal Property Shorthands
√ Proxies
√ Reflect
Generator and Promise
√ Generator function
√ Promises
Class
√ Class
√ super allowed in object methods
√ class ABC extends Array { .. }
Module
× Module export command
× Module import command
=========================================
Passes 39 feature Detections
Your runtime supports 92% of ECMAScript 6
=========================================
从上面可以看出，当前版本的Node.js实际上已经支持了大量的ES6特性和语法，但没有支持包的import export。这类问题可以使用Babel解决，将ES6转换为ES5,这样Node.js就支持了所有的ES6特性了。
