add support for pagination

README.md

@@ -2,11 +2,11 @@
 
 # @radio4000/sdk
 
-A JavaScript SDK to interact with [Radio4000](https://radio4000.com) via a browser or node.js.  
+A JavaScript SDK to interact with [Radio4000](https://radio4000.com) via a browser or node.js.
 
 It offers authentication as well as full create, read, update and delete of users, channels and tracks
 
-## Usage 
+## Usage
 
 ### With browser via CDN
 
@@ -28,8 +28,8 @@ Here's another, where we sign in (use your own credentials), create a channel an
 <script type="module">
   import {sdk} from 'https://cdn.jsdelivr.net/npm/@radio4000/sdk'
 
-  sdk.auth.signIn({email: '', password: '')}
-	
+  sdk.auth.signIn({email: '', password: ''})
+
   const {data: channel, error} = await sdk.channels.createChannel({
     name: 'My radio',
     slug: 'my-radio',
@@ -83,7 +83,7 @@ npm start
 
 ### Environment variables
 
-This SDK connects to the main Radio4000 PostgreSQL database via Supabase. 
+This SDK connects to the main Radio4000 PostgreSQL database via Supabase.
 
 1. `cp .env.example .env`
 2. Fill out the `.env` file

src/channels.js

@@ -1,5 +1,6 @@
 import {supabase} from './main.js'
 import {readUser} from './users.js'
+import {getBrowsePageParams} from './utils.js'
 
 /**
  * A channel
@@ -112,6 +113,21 @@ export const readChannels = async (limit = 1000) => {
 	return supabase.from('channels').select('*').limit(limit).order('created_at', {ascending: true})
 }
 
+/**
+ * Returns a paginated list of channels.
+ * @returns {Promise<ReturnObj>}
+ */
+
+export const browseChannels = async ({page, limit}) => {
+	const { from, to, limitResults } = getBrowsePageParams({ page, limit })
+	return supabase
+		.from('channels')
+		.select('*')
+		.limit(limitResults)
+		.order('created_at', {ascending: true})
+		.range(from, to)
+}
+
 /**
  * Find a Firebase channel by "slug" property
  * @param {string} slug

src/utils.js

@@ -0,0 +1,12 @@
+/*
+	 converts "web component" attributes, to supabase sdk query parameters:
+	 -> page="1" limit="1"
+	 -> from[0] to to[0] limit[0]
+ */
+export const getBrowsePageParams = ({page, limit}) => {
+	let from, to, limitResults;
+	from = (page - 1) * limit
+	to = from + limit - 1
+	limitResults = limit - 1
+	return { from, to, limitResults }
+}