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Endpoint Expiry Policy

By default, Reactive Data Client cache policy can be described as stale-while-revalidate. This means that when data is available it can avoid blocking the application by using the stale data. However, in the background it will still refresh the data if old enough.

Expiry status​

Fresh​

Data in this state is considered new enough that it doesn't need to fetch.

Stale​

Data is still allowed to be shown, however Reactive Data Client might attempt to revalidate by fetching again.

useSuspense() considers fetching on mount as well as when its parameters change. In these cases it will fetch if the data is considered stale.

Invalid​

Data should not be shown. Any components needing this data will trigger fetch (mounted components keep their data until it resolves). If no components care about this data no action will be taken.

Expiry Time​

Endpoint.dataExpiryLength​

Endpoint.dataExpiryLength sets how long (in milliseconds) it takes for data to transition from 'fresh' to 'stale' status. Try setting it to a very low number like '50' to make it becomes stale almost instantly; or a very large number to stay around for a long time.

Toggling between 'first' and 'second' changes the parameters. If the data is still considered fresh you will continue to see the old time without any refresh.

import { lastUpdated } from './api/lastUpdated';

export const getUpdated = lastUpdated.extend({ dataExpiryLength: 10000 });

<script setup lang="ts">
  import { useSuspense } from '@data-client/vue';
  import { getUpdated } from './getUpdated';

  const props = defineProps<{ id: string }>();
  const time = await useSuspense(getUpdated, () => ({ id: props.id }));
</script>

<template>
  <div>
    API time for {{ id }}:
    <time>{{ time.updatedAt.toLocaleString('en-US', { timeStyle: 'long' }) }}</time>
  </div>
</template>
@data-client/rest

Long cache lifetime

LongLivingResource.ts
import {
  RestEndpoint,
  RestGenerics,
  resource,
} from '@data-client/rest';

// We can now use LongLivingEndpoint to create endpoints that will be cached for one hour
class LongLivingEndpoint<
  O extends RestGenerics,
> extends RestEndpoint<O> {
  dataExpiryLength = 60 * 60 * 1000; // one hour
}

const LongLivingResource = resource({
  path: '/:id',
  Endpoint: LongLivingEndpoint,
});

Never retry on error

NoRetryResource.ts
import {
  RestEndpoint,
  RestGenerics,
  resource,
} from '@data-client/rest';

// We can now use NoRetryEndpoint to create endpoints that will be cached for one hour
class NoRetryEndpoint<
  O extends RestGenerics,
> extends RestEndpoint<O> {
  errorExpiryLength = Infinity;
}

const NoRetryResource = resource({
  path: '/:id',
  Endpoint: NoRetryEndpoint,
});

Endpoint.invalidIfStale​

Endpoint.invalidIfStale eliminates the 'stale' status, making data that expires immediately be considered 'invalid'.

This is demonstrated by the component suspending once its data goes stale. If the data is still within the expiry time it just continues to display it.

import { lastUpdated } from './api/lastUpdated';

export const getUpdated = lastUpdated.extend({
  invalidIfStale: true,
  dataExpiryLength: 5000,
});

<script setup lang="ts">
  import { useSuspense } from '@data-client/vue';
  import { getUpdated } from './getUpdated';

  const props = defineProps<{ id: string }>();
  const time = await useSuspense(getUpdated, () => ({ id: props.id }));
</script>

<template>
  <div>
    API time for {{ id }}:
    <time>{{ time.updatedAt.toLocaleString('en-US', { timeStyle: 'long' }) }}</time>
  </div>
</template>

Force refresh​

We sometimes want to fetch new data; while continuing to show the old (stale) data.

A specific endpoint​

Controller.fetch can be used to trigger a fetch while still showing the previous data. This can be done even with 'fresh' data.

<script setup lang="ts">
  import { useController, useSuspense } from '@data-client/vue';
  import { lastUpdated } from './api/lastUpdated';

  const time = await useSuspense(lastUpdated, { id: '1' });
  const ctrl = useController();
</script>

<template>
  <div>
    <time>{{ time.updatedAt.toLocaleString('en-US', { timeStyle: 'long' }) }}</time>
    <button @click="ctrl.fetch(lastUpdated, { id: '1' })">Refresh</button>
  </div>
</template>

Refresh visible endpoints​

Controller.expireAll() sets all responses' expiry status matching testKey to Stale.

<script setup lang="ts">
  import { useController } from '@data-client/vue';
  import { lastUpdated } from './api/lastUpdated';
  import ShowTime from './ShowTime.vue';

  const ctrl = useController();
</script>

<template>
  <div>
    <Suspense v-for="id in ['1', '2', '3']" :key="id">
      <ShowTime :id="id" />
      <template #fallback><div>{{ id }} Loading...</div></template>
    </Suspense>

    <button @click="ctrl.expireAll(lastUpdated)">Expire All</button>
    <button @click="ctrl.fetch(lastUpdated, { id: '1' })">
      Force Refresh First
    </button>
  </div>
</template>

Invalidate​

Both endpoints and entities can be targetted to be invalidated.

Invalidated data always refetches, even when it is fresh. Vue can't suspend a component again once its setup has run, so mounted components keep showing their previous data until the refetch resolves. Meanwhile useCache() returns undefined and useDLE()'s loading is true. Components mounted after invalidation suspend until the new data arrives.

A specific endpoint​

In this example invalidating the endpoint refetches it, even though its data is still fresh.

<script setup lang="ts">
  import { useController } from '@data-client/vue';
  import { lastUpdated } from './api/lastUpdated';
  import ShowTime from './ShowTime.vue';

  const ctrl = useController();
</script>

<template>
  <div>
    <Suspense v-for="id in ['1', '2', '3']" :key="id">
      <ShowTime :id="id" />
      <template #fallback><div>{{ id }} Loading...</div></template>
    </Suspense>

    <button @click="ctrl.invalidateAll(lastUpdated)">Invalidate All</button>
    <button @click="ctrl.invalidate(lastUpdated, { id: '1' })">
      Invalidate First
    </button>
  </div>
</template>

Any endpoint with an entity​

Using the Invalidate schema allows us to invalidate any endpoint that includes that relies on that entity in their response. If the endpoint uses the entity in an Array, it will simply be removed from that Array.

<script setup lang="ts">
  import { Invalidate, RestEndpoint } from '@data-client/rest';
  import { useController, useLoading } from '@data-client/vue';
  import { TimedEntity } from './api/lastUpdated';
  import TimePage from './TimePage.vue';

  const InvalidateTimedEntity = new Invalidate(TimedEntity);
  const deleteLastUpdated = new RestEndpoint({
    path: '/api/currentTime/:id',
    method: 'DELETE',
    schema: InvalidateTimedEntity,
  });

  const ctrl = useController();
  const [handleDelete, loadingDelete] = useLoading(() =>
    ctrl.fetch(deleteLastUpdated, { id: '1' }),
  );
</script>

<template>
  <div>
    <Suspense>
      <TimePage id="1" />
      <template #fallback><div>loading...</div></template>
    </Suspense>
    <button @click="handleDelete">
      {{ loadingDelete ? 'loading...' : 'Invalidate' }}
    </button>
    <button
      @click="ctrl.setResponse(deleteLastUpdated, { id: '1' }, { id: '1' })"
    >
      Invalidate (without fetching DELETE)
    </button>
    <button @click="ctrl.set(InvalidateTimedEntity, { id: '1' }, { id: '1' })">
      Invalidate Entity with ctrl.set
    </button>
  </div>
</template>

Controller.fetch() lets us update the server and store. We can use Controller.setResponse() or Controller.set() when we want to change the local store directly.

Conditional Invalidation based on data​

If invalidation should happen only sometimes, based on the response data, we can return undefined from Entity.process.

class PriceLevel extends Entity {
  price = 0;
  amount = 0;

  pk() {
    return this.price;
  }

  static process(
    input: [number, number],
    parent: any,
    key: string | undefined,
  ): any {
    const [price, amount] = input;
    if (amount === 0) return undefined;
    return { price, amount };
  }
}