The whatwg-fetch package is now a module with exports. The following methods/classes are available:

• fetch
• Headers
• Request
• Response
• DOMException

All exports except for DOMException represent the polyfill implementations, not the native variants if they are available.

This library still automatically acts like a polyfill if native window.fetch is unavailable; there is currently no way to use it as a ponyfill.

Change credentials default value omit → same-origin to match the updated spec.

fetch() and new Request() now accept the signal parameter to accept an AbortSignal.

Join multiple header values with ,<space> instead of , to match other browsers.

Convert any Request/Response unsupported body type to a string to match the spec.

Flow type definitions are now included in the package.