Word
read
Names a query or an action that a screen reads, with its input. It stands as an entry of data, and the view is handed the answer under the name of the entry.
Example
import { screen, read, useTranslations } from 'tentjs/ui'
import { getOrder, currencyRates } from '../functions/orders'
export const orderScreen = screen('orderScreen', {
path: '/orders/:id',
access: 'signedIn',
data: ({ params }) => ({
order: read(getOrder, { id: params.id }, { needed: true }),
rates: read(currencyRates, { base: 'USD' }, { wait: false, refresh: '10 minutes' }),
}),
view: ({ order, rates }) => {
const { format } = useTranslations()
return (
<p>
{order.customer}: {format(order.total, 'currency')}, {rates?.EUR}
</p>
)
},
})read(what, input, options) takes a query or an action as the screen file imported it, its input, and how it is asked. The input is typed by the function's own input, and the answer by its own answer.
A query is asked while the page is drawn, so the first HTML already holds its rows. An action is called read-only: it may read, and whatever would write or send is refused.
Options
| Option | Means |
|---|---|
option.read.needed | needed: true: the screen is not found, with status 404, when the entry answers nothing, and when its query fails as not found: code.T0001, code.T2103, or a fail('not-found', ...) of its own. So the entry is never nothing in its view: a query that may answer no row is read with no check for it, as order.customer in the example, and the type checker holds the view to that. Without needed, the view is handed what the query may answer, nothing among it, and must look before it reads. |
option.read.wait | wait: false: the page is sent without waiting for the entry. Its name is nothing at first, and calls.<name>.busy is true until the answer arrives. It stands on an action and on a query that states heavy. |
option.read.refresh | refresh: '10 minutes': an action is asked again on that timer while the screen is shown. A query states its own. |
Returns
A record that names what is read: { read: 'getOrder', input: { id: '42' }, needed: true }. Nothing is asked when read is called: the page asks through the door.
Errors
code.T1011: refresh is no length of time.
code.T1014: an entry of data that is no read(...).