From 9eb7629ac66abc23b91b81d420891d68bbd4f578 Mon Sep 17 00:00:00 2001
From: Moti Zilberman <moti@fb.com>
Date: Tue, 3 May 2022 12:04:02 -0700
Subject: [PATCH] Add Animated.Numeric Flow type

Summary:
Changelog: [General][Added] - Add `Animated.Numeric` Flow type

Adds a Flow type to represent the various Animated node types that evaluate to numeric values and can be `interpolate()`d.

I'm including `AnimatedInterpolation` as "numeric" here even though it can technically evaluate either to a number or to a string, depending on its config. Note that calling `interpolate()` on a string-valued `AnimatedInterpolation` is a runtime error.

In a future diff, I'm planning to add a type argument to `AnimatedInterpolation` (and its config type), at which point we can refine `Animated.Numeric` to correctly include only `AnimatedInterpolation<number>`.

Reviewed By: javache

Differential Revision: D35869375

fbshipit-source-id: 2ff6754f1a5abc68c9da2c6836872c2022b25676
---
 Libraries/Animated/Animated.js               |  4 ++--
 Libraries/Animated/AnimatedImplementation.js | 13 +++++++++++++
 Libraries/Animated/AnimatedMock.js           |  4 +++-
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/Libraries/Animated/Animated.js b/Libraries/Animated/Animated.js
index 70beabf56a98a9..88fd9dbb188dbe 100644
--- a/Libraries/Animated/Animated.js
+++ b/Libraries/Animated/Animated.js
@@ -16,8 +16,8 @@ import typeof AnimatedSectionList from './components/AnimatedSectionList';
 import typeof AnimatedText from './components/AnimatedText';
 import typeof AnimatedView from './components/AnimatedView';
 
-const AnimatedMock = require('./AnimatedMock');
-const AnimatedImplementation = require('./AnimatedImplementation');
+import * as AnimatedMock from './AnimatedMock';
+import * as AnimatedImplementation from './AnimatedImplementation';
 
 const Animated = ((Platform.isTesting
   ? AnimatedMock
diff --git a/Libraries/Animated/AnimatedImplementation.js b/Libraries/Animated/AnimatedImplementation.js
index 79fbc8a45c0acb..f483d0a63f3647 100644
--- a/Libraries/Animated/AnimatedImplementation.js
+++ b/Libraries/Animated/AnimatedImplementation.js
@@ -551,6 +551,19 @@ const event = function (
   }
 };
 
+// All types of animated nodes that represent scalar numbers and can be interpolated (etc)
+type AnimatedNumeric =
+  | AnimatedAddition
+  | AnimatedDiffClamp
+  | AnimatedDivision
+  | AnimatedInterpolation
+  | AnimatedModulo
+  | AnimatedMultiplication
+  | AnimatedSubtraction
+  | AnimatedValue;
+
+export type {AnimatedNumeric as Numeric};
+
 /**
  * The `Animated` library is designed to make animations fluid, powerful, and
  * easy to build and maintain. `Animated` focuses on declarative relationships
diff --git a/Libraries/Animated/AnimatedMock.js b/Libraries/Animated/AnimatedMock.js
index f2ce29359c2a66..af517502197d53 100644
--- a/Libraries/Animated/AnimatedMock.js
+++ b/Libraries/Animated/AnimatedMock.js
@@ -23,7 +23,7 @@ import type {EndCallback} from './animations/Animation';
 import type {TimingAnimationConfig} from './animations/TimingAnimation';
 import type {DecayAnimationConfig} from './animations/DecayAnimation';
 import type {SpringAnimationConfig} from './animations/SpringAnimation';
-
+import type {Numeric as AnimatedNumeric} from './AnimatedImplementation';
 import AnimatedColor from './nodes/AnimatedColor';
 
 /**
@@ -163,6 +163,8 @@ const loop = function (
   return emptyAnimation;
 };
 
+export type {AnimatedNumeric as Numeric};
+
 module.exports = {
   Value: AnimatedValue,
   ValueXY: AnimatedValueXY,