Merge pull request #1 from satohshi/optional-expand

update

Author: satohshi

.changeset/modern-books-beam.md

@@ -0,0 +1,7 @@
+---
+"pb-option-builder": patch
+---
+
+- Better handling of situations where relation field in "expand" is optional
+- Added autocomplete for "sort"
+- Added support for ":excerpt" modifier

README.md

@@ -9,7 +9,7 @@ This is how you would normally write options for the PocketBase SDK:
     fields: 'id,title,expand.comments(post).user,expand.comments(post).message,expand.tags.id,expand.tags.name'
 }
 ```
-Writing options manually like this is very error-prone and hard to read/maintain.
+Writing options manually like this is very error-prone, and makes the code very hard to read/maintain.
 
 This option builder allows you to write it like this instead:
 ```js
@@ -22,7 +22,7 @@ This option builder allows you to write it like this instead:
     ]
 }
 ```
-It comes with autocomplete for `key`, `fields` and `expand` options, and also provides you a way to **type the response**.
+It comes with autocomplete for `key`, `fields`, `expand` and `sort` options, and also provides you a way to **type the response**.
 
 
 ## Installation
@@ -80,8 +80,10 @@ type Relations = {
 
     // back-relations
     "posts(tags)": Array<Post>
-    "comments(post)": Array<Comment>
-    "comments(user)": Array<Comment>
+
+    // Add "?" modifier to annotate optional relation fields
+    "comments(post)"?: Array<Comment> // i.e. post might not have any comments
+    "comments(user)"?: Array<Comment> // i.e. user might not have any comments
 }
 ```
 
@@ -101,7 +103,7 @@ const [optionsObj, typeObj] = optionBuilder({
     expand: [
         {
             key: 'tags'
-            // returns all fields if it's not specified
+            // returns all fields if not specified
         },
         {
             key: 'comments(post)',
@@ -127,7 +129,7 @@ const result = await pb.collection('posts').getOne<typeof typeObj>(optionsObj);
 It's a bit hacky and not very pretty, but does the job.
 
 
-### Parameter type for `optionBuilder`:
+### Parameter type for the option builder:
 ```ts
 {
     // Table name as defined in "Schema"
@@ -152,7 +154,6 @@ ExpandItem {
     fields?: // same as above
     expand?: // same as above
 }
-
 ```
 
 
@@ -161,7 +162,7 @@ ExpandItem {
 You might run into a situation where you have a component that requires a specific set of fields to be passed to it, and it makes sense to fetch the item directly in one route, but in another, it makes sense to do so through `expand`.
 
 
-Because of the way the argument for the option builder is structured, the `fields` array is portable.  
+Because of the way the parameter for the option builder is structured, the `fields` array is portable.  
 You can define the fields in one place, and use it either at the top level, or in the `expand` option **as is** .
 
 Example:
@@ -199,6 +200,49 @@ const [optionsObj, typeObj] = optionBuilder({
 })
 ```
 
+
+### Handling of optional relation fields 
+Let's say you want to get a post with its comments using `expand`.  
+When the post doesn't have any comments, the SDK (or PocketBase itself rather) returns:
+
+```ts
+{
+    id: "1",
+    title: "Lorem ipsum",
+    tags: ["lorem", "ipsum"],
+    created: "2024-01-01T00:00:00.000Z",
+    updated: "2024-01-01T00:00:00.000Z"
+}
+```
+
+The response won't even have
+
+```ts
+{
+    expand: undefined
+}
+// or
+{
+    expand: {
+        "comments(post)": []
+    }
+}
+```
+
+So if all the specified expands are for optional relation fields, the option builder will add `?` modifier to the expand field itself.  
+i.e. the return type will be:
+
+```ts
+Post & {
+    expand?: {
+        "comments(post)": Comment[]
+    }
+}
+```
+
+If you don't need this much of type-safety and find this behaviour annoying, you can opt out by not adding `?` when defining `Relation`.
+
+
 ## Caveat:
 In order for back-relations to work, you need to have the forward-relations defined as well.
 ```ts
@@ -221,6 +265,7 @@ const [optionsObj, typeObj] = optionBuilder({
 })
 ```
 
+
 ## Why not just integrate this into the SDK?
 - This way, you can start using this in existing projects without having to change anything. I think most of the time, you don't need to pass in any options to the SDK, so installing a new custom SDK for a very few instances where you need to seems like an overkill.
 - There are many functionalities of the official SDK that I don't use or understand fully, and I don't want to maintain a fork of it just for this.