document.cookie binding for S.js signals.

Usage

$ npm i --save @qix/s-cookie

CAVEAT: There are (currently) no events to detect when a document's cookie value has changed. Thus, we elect to poll every 100 milliseconds. This means that multiple changes to a cookie may only update the signal with the final value. Further, we do not check previous values before updating - therefore, using S.data as the factory parameter (which otherwise defaults to S.value) will cause any dependent S computations to run 10 times a second, uncondtionally. Because of this, using the factory parameter is not recommended unless you have a really good reason to use something other than S.value.

import cookieSignal from '@qix/s-cookie';

const session_id = cookieSignal(
    // cookie name to bind to
    'session_id',

    // (optional) options object
    {
        // (optional) initial value
        // (defaults to null)
        init: '1234',

        // (optional, not recommended) signal factory - 
        // either S.value (the default) or S.data
        // (defaults to S.value)
        factory: S.value,

        // (optional) the Domain on which to set the cookie
        // (defaults to null)
        domain: "some.domain.com",

        // (optional) the Path on which to set the cookie
        // (defaults to null)
        path: "/",

        // (boolean, optional) if true, sets Secure
        // (defaults to false)
        secure: true
    }
);

S.root(() => {
    // Signal -> Cookie binding
    console.log(document.cookie); //-> session_id=1234
    session_id("5678");
    console.log(document.cookie); //-> session_id=5678

    // Cookie -> Signal binding (latency: 100ms)
    console.log(session_id()); //-> 5678
    document.cookie = 'session_id=abcd';
    console.log(session_id()); //-> abcd (may take 100ms to show up)

    // Expiration (by signal)
    console.log(document.cookie) //-> session_id=abcd
    session_id(null);
    console.log(document.cookie) // <no output>

    // Expiration (via cookie expiration)
    //  (setting the age to max-age=0 forces expiration, but
    //  this will also be the case if the server sets an expiration
    //  date/time or a maximum age as well)
    session_id('wxyz');
    document.cookie = 'session_id=; max-age=0';
    console.log(session_id()); //-> null
});

Package detail

@qix/s-cookie

readme

Usage

License