Make results of SELECT.one nullable (#374)

CHANGELOG.md

@@ -20,6 +20,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/).
 - Use `Required` instead of `DeepRequired` in projection function to avoid complexity errors from TypeScript
 - Added missing type inference for `.set`/`.with` of `UPDATE`
 - Added missing type inference for `.entries` of `UPSERT` and `INSERT`
+- Variants of `SELECT.one(T)` will now return `T | null`, instead of `T`
 
 ## Version 0.8.0 - 24-11-26
 

apis/ql.d.ts

@@ -131,17 +131,17 @@ type SELECT_one =
 // calling with class
   (<T extends ArrayConstructable>
   (entityType: T, projection?: Projection<QLExtensions<SingularInstanceType<T>>>)
-  => Awaitable<SELECT<SingularInstanceType<T>, SELECT_one>, SingularInstanceType<T>>)
+  => Awaitable<SELECT<SingularInstanceType<T>, SELECT_one>, SingularInstanceType<T> | null>)
 &
   (<T extends ArrayConstructable>
   (entityType: T, primaryKey: PK, projection?: Projection<QLExtensions<SingularInstanceType<T>>>)
-  => Awaitable<SELECT<SingularInstanceType<T>, SELECT_one>, SingularInstanceType<T>>)
+  => Awaitable<SELECT<SingularInstanceType<T>, SELECT_one>, SingularInstanceType<T> | null>)
 
   & ((entity: EntityDescription, primaryKey?: PK, projection?: Projection<unknown>) => SELECT<_TODO, SELECT_one>)
-  & (<T> (entity: T[], projection?: Projection<T>) => Awaitable<SELECT<T, SELECT_one>, T>)
-  & (<T> (entity: T[], primaryKey: PK, projection?: Projection<T>) => Awaitable<SELECT<T, SELECT_one>, T>)
-  & (<T> (entity: { new(): T }, projection?: Projection<T>) => Awaitable<SELECT<T, SELECT_one>, T>)
-  & (<T> (entity: { new(): T }, primaryKey: PK, projection?: Projection<T>) => Awaitable<SELECT<T, SELECT_one>, T>)
+  & (<T> (entity: T[], projection?: Projection<T>) => Awaitable<SELECT<T, SELECT_one>, T | null>)
+  & (<T> (entity: T[], primaryKey: PK, projection?: Projection<T>) => Awaitable<SELECT<T, SELECT_one>, T | null>)
+  & (<T> (entity: { new(): T }, projection?: Projection<T>) => Awaitable<SELECT<T, SELECT_one>, T | null>)
+  & (<T> (entity: { new(): T }, primaryKey: PK, projection?: Projection<T>) => Awaitable<SELECT<T, SELECT_one>, T | null>)
   & ((subject: ref) => SELECT<_TODO>)
 
 type SELECT_from =
@@ -155,7 +155,7 @@ type SELECT_from =
 &
   (<E extends ArrayConstructable>
   (entityType: E, primaryKey: PK, projection?: Projection<SingularInstanceType<E>>)
-  => Awaitable<SELECT<SingularInstanceType<E>>, SingularInstanceType<E>>) // when specifying a key, we expect a single element as result
+  => Awaitable<SELECT<SingularInstanceType<E>>, SingularInstanceType<E> | null>) // when specifying a key, we expect a single element as result
 // calling with definition
   & (<T>(entity: EntityDescription, primaryKey?: PK, projection?: Projection<T>) => SELECT<T>)
 // calling with concrete list

test/typescript/apis/project/cds-ql.ts

@@ -114,7 +114,7 @@ DELETE(Foo)
 DELETE(Foo, Foos)
 DELETE([Foo, Foos])
 
-let selectOne: Foo
+let selectOne: Foo | null
 let selectMany: Foos
 
 // SINGULAR TESTS
@@ -125,6 +125,7 @@ selectOne = await SELECT(Foo, 42)
 selectOne = await SELECT.one.from(Foo)
 selectOne = await SELECT.one.from(Foo, 42)
 selectOne = await SELECT.one.from(Foo, 42)
+const xx = await SELECT.one(Foo, 42)
 selectOne = await SELECT.one.from(Foo, 42, f => f.x)
 selectOne = await SELECT.one.from(Foo, f => f.x)
 selectOne = await SELECT.one.from(Foo).alias('Bars')
@@ -237,17 +238,17 @@ SELECT.from `Books` .columns ( 'title', {ref:['author','name'],as:'author'} )
 SELECT.from `Books` .columns (['title', {ref:['author','name'],as:'author'} ])
 
 // @ts-expect-error invalid key of result
-SELECT.one.from(Foos).columns(['entityIDColumn', 'parentIDColumn']).then(r => r.some)
-SELECT.one.from(Foos).columns(['entityIDColumn', 'parentIDColumn']).then(r => r.ref)
+SELECT.one.from(Foos).columns(['entityIDColumn', 'parentIDColumn']).then(r => r?.some)
+SELECT.one.from(Foos).columns(['entityIDColumn', 'parentIDColumn']).then(r => r?.ref)
 // @ts-expect-error invalid key of result
-SELECT.one.from(Foos).columns('entityIDColumn', 'parentIDColumn').then(r => r.some)
-SELECT.one.from(Foos).columns('entityIDColumn', 'parentIDColumn').then(r => r.ref)
+SELECT.one.from(Foos).columns('entityIDColumn', 'parentIDColumn').then(r => r?.some)
+SELECT.one.from(Foos).columns('entityIDColumn', 'parentIDColumn').then(r => r?.ref)
 // @ts-expect-error invalid key of result
-SELECT.one.from(Foos).columns([{ ref: ['entityIDColumn'] }]).then(r => r.some)
-SELECT.one.from(Foos).columns([{ ref: ['entityIDColumn'] }]).then(r => r.ref)
+SELECT.one.from(Foos).columns([{ ref: ['entityIDColumn'] }]).then(r => r?.some)
+SELECT.one.from(Foos).columns([{ ref: ['entityIDColumn'] }]).then(r => r?.ref)
 // @ts-expect-error invalid key of result
-SELECT.one.from(Foos).columns({ ref: ['entityIDColumn'] }).then(r => r.some)
-SELECT.one.from(Foos).columns({ ref: ['entityIDColumn'] }).then(r => r.ref)
+SELECT.one.from(Foos).columns({ ref: ['entityIDColumn'] }).then(r => r?.some)
+SELECT.one.from(Foos).columns({ ref: ['entityIDColumn'] }).then(r => r?.ref)
 
 INSERT.into(Foos).values([1,2,3])