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Cookie ​

To use Cookie, you can extract the cookie property and access its name and value directly.

There's no get/set, you can extract the cookie name and retrieve or update its value directly.

ts
app.get('/', ({ cookie: { name } }) => {
    // Get
    name.value

    // Set
    name.value = "New Value"
    name.value = {
        hello: 'world'
    }
})
app.get('/', ({ cookie: { name } }) => {
    // Get
    name.value

    // Set
    name.value = "New Value"
    name.value = {
        hello: 'world'
    }
})

By default, Reactive Cookie can encode/decode type of object automatically. So if you like to set the cookie as an object, it will just work.

Reactivity ​

Elysia cookie is reactive, based on approach like signal.

Elysia cookie can sync the value of cookie, and set-headers automatically, providing a single source of truth for handling cookie.

If you don't set the new value for the cookie, the Set-Cookie header will not be send to keep the same cookie value, so you don't have to worry about the performance.

By default, cookie is an object that rely on Proxy, so the extract value can never be undefined, it will always be a value of Cookie<unknown>, which you can retrieve its value by calling .value property.

If you iterate over the cookie jar, the value will be only iterated over an existing cookie value, so you can treat it as a normal object.

To use Cookie attribute, you can either use one of the following:

  1. Setting the property directly
  2. Using set or add to update cookie property.

See cookie attribute config for more information.

Assign Property ​

You can get/set the property of a cookie as if it's a normal object, the reactivity model will sync the cookie value automatically.

ts
app.get('/', ({ cookie: { name } }) => {
    // get
    name.domain

    // set
    name.domain = 'millennium.sh'
    name.httpOnly = true
})
app.get('/', ({ cookie: { name } }) => {
    // get
    name.domain

    // set
    name.domain = 'millennium.sh'
    name.httpOnly = true
})

set ​

set allow us to set update multiple cookie property all at once, by reset all property and overwrite it with a new value.

ts
app.get('/', ({ cookie: { name } }) => {
    name.set({
        domain: 'millennium.sh',
        httpOnly: true
    })
})
app.get('/', ({ cookie: { name } }) => {
    name.set({
        domain: 'millennium.sh',
        httpOnly: true
    })
})

add ​

Like set, add allow us to update multiple cookie property at once, but instead, will only overwrite the property defined instead of resetting.

remove ​

To remove a cookie, you can either use:

  1. name.remove
  2. delete cookie.name
ts
app.get('/', ({ cookie, cookie: { name } }) => {
    name.remove()

    delete cookie.name
})
app.get('/', ({ cookie, cookie: { name } }) => {
    name.remove()

    delete cookie.name
})

You can strictly validate cookie type and providing type inference for cookie by using cookie schema with t.Cookie.

ts
app.get('/', ({ cookie: { name } }) => {
    // Set
    name.value = {
        id: 617,
        name: 'Summoning 101'
    }
}, {
    cookie: t.Cookie({
        value: t.Object({
            id: t.Numeric(),
            name: t.String()
        })
    })
})
app.get('/', ({ cookie: { name } }) => {
    // Set
    name.value = {
        id: 617,
        name: 'Summoning 101'
    }
}, {
    cookie: t.Cookie({
        value: t.Object({
            id: t.Numeric(),
            name: t.String()
        })
    })
})

To handle nullable cookie value, you can use t.Optional on cookie name you want to be nullable.

ts
app.get('/', ({ cookie: { name } }) => {
    // Set
    name.value = {
        id: 617,
        name: 'Summoning 101'
    }
}, {
    cookie: t.Cookie({
        value: t.Optional(
            t.Object({
                id: t.Numeric(),
                name: t.String()
            })
        )
    })
})
app.get('/', ({ cookie: { name } }) => {
    // Set
    name.value = {
        id: 617,
        name: 'Summoning 101'
    }
}, {
    cookie: t.Cookie({
        value: t.Optional(
            t.Object({
                id: t.Numeric(),
                name: t.String()
            })
        )
    })
})