Edge Runtime

Edge Runtime用于中间件，并支持以下API：

网络API

API	描述
Blob	表示一个blob
fetch	获取资源
FetchEvent	表示一个获取事件
File	表示一个文件
FormData	表示表单数据
Headers	表示HTTP头
Request	表示一个HTTP请求
Response	表示一个HTTP响应
URLSearchParams	表示URL搜索参数
WebSocket	表示一个websocket连接

编码API

API	描述
atob	解码base-64编码的字符串
btoa	将字符串编码为base-64
TextDecoder	将Uint8Array解码为字符串
TextDecoderStream	可链接的流解码器
TextEncoder	将字符串编码为Uint8Array
TextEncoderStream	可链接的流编码器

Stream APIs

API	描述
ReadableStream	表示一个可读流
ReadableStreamBYOBReader	表示一个ReadableStream的读取器
ReadableStreamDefaultReader	表示一个ReadableStream的读取器
TransformStream	表示一个转换流
WritableStream	表示一个可写流
WritableStreamDefaultWriter	表示一个WritableStream的写入器

Crypto APIs

API	描述
crypto	提供对平台加密功能的访问
CryptoKey	表示一个加密密钥
SubtleCrypto	提供对常见加密原语的访问，如哈希、签名、加密或解密

Web Standard APIs

API	Description
AbortController	Allows you to abort one or more DOM requests as and when desired
Array	Represents an array of values
ArrayBuffer	Represents a generic, fixed-length raw binary data buffer
Atomics	Provides atomic operations as static methods
BigInt	Represents a whole number with arbitrary precision
BigInt64Array	Represents a typed array of 64-bit signed integers
BigUint64Array	Represents a typed array of 64-bit unsigned integers
Boolean	Represents a logical entity and can have two values: true and false
clearInterval	Cancels a timed, repeating action which was previously established by a call to setInterval()
clearTimeout	Cancels a timed, repeating action which was previously established by a call to setTimeout()
console	Provides access to the browser's debugging console
DataView	Represents a generic view of an ArrayBuffer
Date	Represents a single moment in time in a platform-independent format
decodeURI	Decodes a Uniform Resource Identifier (URI) previously created by encodeURI or by a similar routine
decodeURIComponent	Decodes a Uniform Resource Identifier (URI) component previously created by encodeURIComponent or by a similar routine
DOMException	Represents an error that occurs in the DOM
encodeURI	Encodes a Uniform Resource Identifier (URI) by replacing each instance of certain characters by one, two, three, or four escape sequences representing the UTF-8 encoding of the character
encodeURIComponent	Encodes a Uniform Resource Identifier (URI) component by replacing each instance of certain characters by one, two, three, or four escape sequences representing the UTF-8 encoding of the character
Error	Represents an error when trying to execute a statement or accessing a property
EvalError	Represents an error that occurs regarding the global function eval()
Float32Array	Represents a typed array of 32-bit floating point numbers
Float64Array	Represents a typed array of 64-bit floating point numbers
Function	Represents a function
Infinity	Represents the mathematical Infinity value
Int8Array	Represents a typed array of 8-bit signed integers
Int16Array	Represents a typed array of 16-bit signed integers
Int32Array	Represents a typed array of 32-bit signed integers
Intl	Provides access to internationalization and localization functionality
isFinite	Determines whether a value is a finite number
isNaN	Determines whether a value is NaN or not
JSON	Provides functionality to convert JavaScript values to and from the JSON format
Map	Represents a collection of values, where each value may occur only once
Math	Provides access to mathematical functions and constants
Number	Represents a numeric value
Object	Represents the object that is the base of all JavaScript objects
parseFloat	Parses a string argument and returns a floating point number
parseInt	Parses a string argument and returns an integer of the specified radix
Promise	Represents the eventual completion (or failure) of an asynchronous operation, and its resulting value
Proxy	Represents an object that is used to define custom behavior for fundamental operations (e.g. property lookup, assignment, enumeration, function invocation, etc)
queueMicrotask	Queues a microtask to be executed
RangeError	Represents an error when a value is not in the set or range of allowed values
ReferenceError	Represents an error when a non-existent variable is referenced
Reflect	Provides methods for interceptable JavaScript operations
RegExp	Represents a regular expression, allowing you to match combinations of characters
Set	Represents a collection of values, where each value may occur only once
setInterval	Repeatedly calls a function, with a fixed time delay between each call
setTimeout	Calls a function or evaluates an expression after a specified number of milliseconds
SharedArrayBuffer	Represents a generic, fixed-length raw binary data buffer
String	Represents a sequence of characters
structuredClone	Creates a deep copy of a value
Symbol	Represents a unique and immutable data type that is used as the key of an object property
SyntaxError	Represents an error when trying to interpret syntactically invalid code
TypeError	Represents an error when a value is not of the expected type
Uint8Array	Represents a typed array of 8-bit unsigned integers
Uint8ClampedArray	Represents a typed array of 8-bit unsigned integers clamped to 0-255
Uint32Array	Represents a typed array of 32-bit unsigned integers
URIError	Represents an error when a global URI handling function was used in a wrong way
URL	Represents an object providing static methods used for creating object URLs
URLPattern	Represents a URL pattern
URLSearchParams	Represents a collection of key/value pairs
WeakMap	Represents a collection of key/value pairs in which the keys are weakly referenced
WeakSet	Represents a collection of objects in which each object may occur only once
WebAssembly	Provides access to WebAssembly

Next.js 特定 Polyfills

• AsyncLocalStorage

环境变量

你可以使用 process.env 来访问 环境变量，这适用于 next dev 和 next build。

不支持的 API

Edge 运行时有一些限制，包括：

• 原生 Node.js API 不被支持。例如，你不能读取或写入文件系统。
• node_modules 可以使用，只要它们实现了 ES 模块并不使用原生 Node.js API。
• 直接调用 require 是 不被允许 的。请改用 ES 模块。

以下 JavaScript 语言特性被禁用，将无法工作：

API	描述
eval	评估表示为字符串的 JavaScript 代码
new Function(evalString)	使用作为参数提供的代码创建一个新的函数
WebAssembly.compile	从缓冲区源编译 WebAssembly 模块
WebAssembly.instantiate	从缓冲区源编译并实例化 WebAssembly 模块

在极少数情况下，你的代码可能包含（或导入）一些动态代码评估语句，这些语句在运行时无法到达，并且不能通过摇树（tree shaking）移除。 你可以通过中间件配置放宽检查，以允许特定文件：

export const config = {
  unstable_allowDynamic: [
    // 允许单个文件
    '/lib/utilities.js',
    // 使用 glob 允许 function-bind 第三方模块中的任何内容
    '/node_modules/function-bind/**',
  ],
}

unstable_allowDynamic 是一个 glob，或 glob 数组，忽略特定文件的动态代码评估。这些 glob 相对于你的应用程序根文件夹。

须知，如果这些语句在 Edge 上执行，它们将抛出异常并导致运行时错误。