From 9aa198b1667808d5d610b5498ffc4d0e1fb66371 Mon Sep 17 00:00:00 2001
From: Ricardo Berdejo <ricbermo@users.noreply.github.com>
Date: Wed, 27 Jul 2022 17:58:00 +0000
Subject: [PATCH] feat: partial selection (#274)

---
 README.md            |  8 ++++++++
 src/paginate.spec.ts | 40 ++++++++++++++++++++++++++++++++++++++++
 src/paginate.ts      | 13 +++++++++++++
 3 files changed, 61 insertions(+)

diff --git a/README.md b/README.md
index 03b8979..4053b8b 100644
--- a/README.md
+++ b/README.md
@@ -171,6 +171,14 @@ const paginateConfig: PaginateConfig<CatEntity> {
    */
   searchableColumns: ['name', 'color'],
 
+  /**
+   * Required: false
+   * Type: TypeORM partial selection
+   * Default: None
+   * https://typeorm.io/select-query-builder#partial-selection
+   */
+  select: ['name', 'color'],
+
   /**
    * Required: false
    * Type: number
diff --git a/src/paginate.spec.ts b/src/paginate.spec.ts
index cc612db..4a30671 100644
--- a/src/paginate.spec.ts
+++ b/src/paginate.spec.ts
@@ -841,4 +841,44 @@ describe('paginate', () => {
         const result = await paginate<CatEntity>(query, catRepo, config)
         expect(result.meta.totalItems).toBe(cats.length - 1)
     })
+
+    it('should return the specified columns only', async () => {
+        const config: PaginateConfig<CatEntity> = {
+            sortableColumns: ['id'],
+            select: ['id', 'name'],
+        }
+        const query: PaginateQuery = {
+            path: '',
+        }
+
+        const result = await paginate<CatEntity>(query, catRepo, config)
+
+        result.data.forEach((cat) => {
+            expect(cat.color).not.toBeDefined()
+        })
+    })
+
+    it('should return the specified relationship columns only', async () => {
+        const config: PaginateConfig<CatEntity> = {
+            sortableColumns: ['name'],
+            select: ['id', 'name', 'toys.name'],
+            relations: ['toys'],
+        }
+        const query: PaginateQuery = {
+            path: '',
+        }
+
+        const result = await paginate<CatEntity>(query, catRepo, config)
+
+        result.data.forEach((cat) => {
+            expect(cat.id).toBeDefined()
+            expect(cat.name).toBeDefined()
+            expect(cat.color).not.toBeDefined()
+
+            cat.toys.map((toy) => {
+                expect(toy.name).toBeDefined()
+                expect(toy.id).not.toBeDefined()
+            })
+        })
+    })
 })
diff --git a/src/paginate.ts b/src/paginate.ts
index 6c56949..4bcbf91 100644
--- a/src/paginate.ts
+++ b/src/paginate.ts
@@ -47,6 +47,7 @@ export interface PaginateConfig<T> {
     relations?: RelationColumn<T>[]
     sortableColumns: Column<T>[]
     searchableColumns?: Column<T>[]
+    select?: Column<T>[]
     maxLimit?: number
     defaultSortBy?: SortBy<T>
     defaultLimit?: number
@@ -224,6 +225,18 @@ export async function paginate<T>(
         }
     }
 
+    if (config.select?.length > 0) {
+        const mappedSelect = config.select.map((col) => {
+            if (col.includes('.')) {
+                const [rel, relCol] = col.split('.')
+                return `${queryBuilder.alias}_${rel}.${relCol}`
+            }
+
+            return `${queryBuilder.alias}.${col}`
+        })
+        queryBuilder.select(mappedSelect)
+    }
+
     if (config.where) {
         queryBuilder.andWhere(new Brackets((qb) => qb.andWhere(config.where)))
     }