libcors1.0.1 • Public • Published
libcors, of course
CORS handling, 100% transportation agnostic. Is bundled with TypeScript type information.
This package is heavily influenced by
corser for its logic. It is more or less hand-translated from
corser line by line into TypeScript and by removing the dependencies on
Of the other libraries out there handling CORS,
koa-cors etc, none of them are pure CORS related, but are coupled with express or koa or Node.js'
http modules, and they potentially alter the corresponding
This package provides purely the logic for CORS.
There is no mutable global state being stored within this module. Each instance you create contains its own state. Expect no magic.
The package exports one function;
This function initializes a new CORS context given a set of options (if any). The return value is a function that can be called with a method and a set of headers to return (a promise to) CORS properties.
const corsFn = ;// We get these from somewhere:const method; // 'GET', 'POST', etcconst headers; // key-value of stringsconst corsResult = await ;
Don't forget that
corsFn returns a promise which needs to be
The options which can be provided to
origins is either an array of strings or a function taking the
Origin header as argument (a string) and returns a boolean (or a promise to a boolean).
requestHeaders defaults to
[ "accept", "accept-language", "content-language", "content-type" ] and
responseHeaders defaults to
[ "cache-control", "content-language", "content-type", "expires", "last-modified", "pragma" ].
corsResult above is defined by the TypeScript interface
headers is a key-value lookup of headers that should be sent back in the response and the
vary is a list of fields that should be appended to the
status is defined, this means the response should be sent immediately (without allowing further middlewares/routes) and the HTTP response code should be set to this value.
if ( !status ), the normal route flow should continue.
Usage as a middleware
The package is 100% transport/framework agnostic, so to use it as a middleware in a framework, a wrapping package should be used instead where this provides the pure logic.