defer priming second page

packages/model.mixins.pager/CHANGELOG.md

@@ -3,6 +3,16 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+## [3.0.0](https://github.com/Profiscience/knockout-contrib/compare/@profiscience/[email protected]...@profiscience/[email protected]) (2025-05-05)
+
+### ✅ Summary of Changes:
+
+- **Added** a `primeSecondPage` optional parameter to `PagerMixin`, defaulting to `false`.
+- **Modified** the `PRIME_PAGER` method to conditionally fetch page 2 based on `primeSecondPage`.
+- **Updated** `constructor` and `update()` to pass `primeSecondPage` to `PRIME_PAGER`.
+- **⚠️ Breaking Change**: Previously, page 2 was always loaded during initialization. This change **defers the loading of page 2** unless `primeSecondPage` is explicitly set to `true`.  
+  → **This is designed to reduce server load and improve perceived performance** on first load.
+
 ## [2.1.11](https://github.com/Profiscience/knockout-contrib/compare/@profiscience/[email protected]...@profiscience/[email protected]) (2020-10-09)
 
 **Note:** Version bump only for package @profiscience/knockout-contrib-model-mixins-pager

packages/model.mixins.pager/index.ts

@@ -27,7 +27,8 @@ export function PagerMixin<
   property: keyof TData,
   strategy: PaginationStrategy<TParams> = ((page: number) => ({
     page,
-  })) as PaginationStrategy<any>
+  })) as PaginationStrategy<any>,
+  primeSecondPage: boolean = false
 ) {
   return <
     T extends new (...args: any[]) => DataModelConstructorBuilder<
@@ -47,34 +48,36 @@ export function PagerMixin<
         Object.assign(args[0], strategy(1))
         super(...args)
 
-        this[PAGER] = this[CREATE_PAGER]()
+        this[PAGER] = this[CREATE_PAGER]() // Setup pager generator
         this.hasMore = ko.observable(true)
-
         // ensure method is called with correct "this" value
         this.getMore = this.getMore.bind(this)
 
         const initialized = this[INITIALIZED]
-        this[INITIALIZED] = initialized
-          // @TODO unchain this when proper error handling is implemented
-          .then(() => this[PRIME_PAGER]())
+        this[INITIALIZED] = primeSecondPage
+          ? initialized.then(() => this[PRIME_PAGER]())
+          : initialized
       }
 
+      /** Manually fetch the next page of data */
       public async getMore(): Promise<boolean> {
         this.loading(true)
         const { done } = await this[PAGER].next()
         this.loading(false)
         return !done
       }
 
+      /** Resets pager and reloads starting from page 1 */
       protected update() {
         Object.assign(this.params, strategy(1))
         this[PAGER] = this[CREATE_PAGER]()
         const p = super.update()
-        return p.then(() => this[PRIME_PAGER]())
+        return p.then(() => primeSecondPage ? this[PRIME_PAGER]() : undefined)
       }
 
+      /** Generator to yield control between page loads */
       private async *[CREATE_PAGER](): AsyncIterableIterator<void> {
-        let page = 2
+        let page = 2 // Page 1 already loaded by base model
 
         Object.assign(this.params, strategy(page))
 
@@ -98,6 +101,7 @@ export function PagerMixin<
         } while (this.hasMore())
       }
 
+      /** Loads the first yield from the pager (usually page 2) */
       private async [PRIME_PAGER]() {
         await this[PAGER].next()
       }

packages/model.mixins.pager/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@profiscience/knockout-contrib-model-mixins-pager",
-  "version": "2.1.11",
+  "version": "3.0.0",
   "license": "WTFPL",
   "author": "Casey Webb (https://caseyWebb.xyz)",
   "homepage": "https://profiscience.github.io/knockout-contrib/packages/model.mixins.pager",