Prefetch

The prefetch plugin lets you load data ahead of time, so it's ready when the user navigates.

Installation

npm install @spoosh/plugin-prefetch

Usage

import { Spoosh } from "@spoosh/core";
import { prefetchPlugin } from "@spoosh/plugin-prefetch";
import { cachePlugin } from "@spoosh/plugin-cache";

const spoosh = new Spoosh<ApiSchema, Error>("/api").use([
  prefetchPlugin(),
  cachePlugin({ staleTime: 5000 }),
]);

const { injectRead, injectWrite, prefetch } = create(spoosh);

Basic Prefetch

// Prefetch data
await prefetch((api) => api("posts").GET());

// Prefetch with query parameters
await prefetch((api) => api("posts").GET({ query: { page: 1, limit: 10 } }));

Prefetch with Options

Pass plugin options as the second argument:

await prefetch((api) => api("users/:id").GET({ params: { id: userId } }), {
  staleTime: 60000,
  retry: { retries: 3 },
});

Prefetch on Hover

A common pattern is prefetching when the user hovers over a link:

@Component({
  selector: "app-post-link",
  template: `
    <a [routerLink]="['/posts', 1]" (mouseenter)="onHover()"> View Post </a>
  `,
})
export class PostLinkComponent {
  onHover() {
    prefetch((api) => api("posts/:id").GET({ params: { id: 1 } }));
  }
}

Prefetch on Route Change

Prefetch data before navigating:

@Component({
  selector: "app-nav",
  template: ` <button (click)="handleNavigation(postId)">View Post</button> `,
})
export class NavComponent {
  constructor(private router: Router) {}

  async handleNavigation(postId: number) {
    await prefetch((api) => api("posts/:id").GET({ params: { id: postId } }));
    this.router.navigate(["/posts", postId]);
  }
}

In-Flight Deduplication

Multiple calls to prefetch the same data will return the same promise, avoiding duplicate network requests. This is built into the prefetch plugin - no deduplication plugin required.

// These will only make ONE network request
prefetch((api) => api("posts").GET());
prefetch((api) => api("posts").GET());
prefetch((api) => api("posts").GET());

Custom Tags

By default, a tag is auto-generated from the resolved path. You can override with custom tags:

// Auto-generated tag (default)
await prefetch((api) => api("users/:id/posts").GET({ params: { id: "123" } }));
// → tag: "users/123/posts"

// Single custom tag
await prefetch((api) => api("posts").GET(), {
  tags: "my-posts",
});
// → tag: "my-posts"

// Multiple custom tags
await prefetch((api) => api("posts").GET(), {
  tags: ["posts", "dashboard"],
});
// → tags: ["posts", "dashboard"]

Options

Plugin Config

Option	Type	Default	Description
`staleTime`	`number`	-	Default stale time for prefetched data (ms)
`timeout`	`number`	`30000`	Timeout to auto-clear stale promises (ms). Prevents memory leaks from requests that never settle.

Prefetch Options

The second argument accepts any plugin options plus:

Option	Type	Description
`tags`	`string \| string[]`	Custom tags (overrides auto-generated tag)

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