From 831001a9c5e246aea4d6db3e0d88b45c3f5bd9c8 Mon Sep 17 00:00:00 2001
From: Jerko Steiner <jerko.steiner@gmail.com>
Date: Wed, 3 Apr 2019 18:02:36 +0800
Subject: [PATCH] Add createFilterProps

---
 packages/common/src/filterProps.test.ts | 35 +++++++++++++++++++++++++
 packages/common/src/filterProps.ts      |  8 ++++++
 packages/common/src/index.ts            |  1 +
 3 files changed, 44 insertions(+)
 create mode 100644 packages/common/src/filterProps.test.ts
 create mode 100644 packages/common/src/filterProps.ts

diff --git a/packages/common/src/filterProps.test.ts b/packages/common/src/filterProps.test.ts
new file mode 100644
index 0000000..ac696e5
--- /dev/null
+++ b/packages/common/src/filterProps.test.ts
@@ -0,0 +1,35 @@
+import {createFilterProps} from './filterProps'
+
+interface IEntity {
+  readonly id: number
+}
+
+interface IPerson {
+  readonly firstName: string
+  readonly lastName: string
+}
+
+interface IPersonEntity extends IEntity, IPerson {}
+
+describe('filterProps', () => {
+
+  const p: IPersonEntity = {
+    id: 1,
+    firstName: 'John',
+    lastName: 'Smith',
+  }
+
+  const filterProps = createFilterProps<IPerson>({
+    firstName: true,
+    lastName: true,
+  })
+
+  it('picks only relevant props', () => {
+    const person = filterProps(p)
+    expect(person).toEqual({
+      firstName: 'John',
+      lastName: 'Smith',
+    })
+  })
+
+})
diff --git a/packages/common/src/filterProps.ts b/packages/common/src/filterProps.ts
new file mode 100644
index 0000000..67cbbd8
--- /dev/null
+++ b/packages/common/src/filterProps.ts
@@ -0,0 +1,8 @@
+export function createFilterProps<T>(schema: Record<keyof T & string, true>) {
+  return function filterProps<U extends T>(item: U): T {
+    return Object.keys(schema).reduce((obj: T, key) => {
+      obj[key as keyof T] = item[key as keyof T]
+      return obj
+    }, {} as T)
+  }
+}
diff --git a/packages/common/src/index.ts b/packages/common/src/index.ts
index 7e57cae..23219da 100644
--- a/packages/common/src/index.ts
+++ b/packages/common/src/index.ts
@@ -10,6 +10,7 @@ export * from './IUser'
 export * from './IUserInTeam'
 export * from './IUserTeam'
 export * from './URLFormatter'
+export * from './filterProps'
 export * from './indexBy'
 export * from './types'
 export * from './without'