add extrapolate shortcut interp([..],[..],'clamp')

Author: drcmda

src/animated/AnimatedInterpolation.ts

@@ -1,7 +1,7 @@
 import { SpringValue } from '../types/animated'
 import { InterpolationConfig } from '../types/interpolation'
 import Animated, { AnimatedArray } from './Animated'
-import createInterpolator from './createInterpolator'
+import createInterpolator, { ExtrapolateType } from './createInterpolator'
 
 type IpValue = string | number | (string | number)[]
 // The widest possible interpolator type, possible if interpolate() is passed
@@ -15,7 +15,8 @@ export default class AnimatedInterpolation extends AnimatedArray<Animated>
   constructor(
     parents: Animated | Animated[],
     range: number[] | InterpolationConfig | Interpolator,
-    output?: (number | string)[]
+    output?: (number | string)[],
+    extrapolate?: ExtrapolateType
   ) {
     super()
     this.payload =
@@ -25,7 +26,11 @@ export default class AnimatedInterpolation extends AnimatedArray<Animated>
         : Array.isArray(parents)
         ? parents
         : [parents]
-    this.calc = createInterpolator(range as number[], output!) as Interpolator
+    this.calc = createInterpolator(
+      range as number[],
+      output!,
+      extrapolate
+    ) as Interpolator
   }
 
   public getValue() {
@@ -34,15 +39,26 @@ export default class AnimatedInterpolation extends AnimatedArray<Animated>
 
   public updateConfig(
     range: number[] | InterpolationConfig | Interpolator,
-    output?: (number | string)[]
+    output?: (number | string)[],
+    extrapolate?: ExtrapolateType
   ) {
-    this.calc = createInterpolator(range as number[], output!) as Interpolator
+    this.calc = createInterpolator(
+      range as number[],
+      output!,
+      extrapolate
+    ) as Interpolator
   }
 
   public interpolate(
     range: number[] | InterpolationConfig | ((...args: any[]) => IpValue),
-    output?: (number | string)[]
+    output?: (number | string)[],
+    extrapolate?: ExtrapolateType
   ): AnimatedInterpolation {
-    return new AnimatedInterpolation(this, range as number[], output!)
+    return new AnimatedInterpolation(
+      this,
+      range as number[],
+      output!,
+      extrapolate
+    )
   }
 }

src/animated/createInterpolator.ts

@@ -1,7 +1,7 @@
 import { EasingFunction, InterpolationConfig } from '../types/interpolation'
 import * as Globals from './Globals'
 
-type ExtrapolateType = InterpolationConfig['extrapolate']
+export type ExtrapolateType = InterpolationConfig['extrapolate']
 
 // The most generic interpolation value, possible with custom interpolation functions.
 type IpValue = string | number | (string | number)[]
@@ -16,7 +16,11 @@ function createInterpolator<
 function createInterpolator<
   In extends number | string,
   Out extends number | string
->(range: number[], output: Out[]): (input: In) => Out
+>(
+  range: number[],
+  output: Out[],
+  extrapolate: ExtrapolateType
+): (input: In) => Out
 function createInterpolator(
   range: number[] | InterpolationConfig | ((...input: IpValue[]) => IpValue),
   output?: (number | string)[],
@@ -26,11 +30,7 @@ function createInterpolator(
     return range
   }
   if (Array.isArray(range)) {
-    return createInterpolator({
-      range,
-      output: output!,
-      extrapolate,
-    })
+    return createInterpolator({ range, output: output!, extrapolate })
   }
   if (Globals.interpolation && typeof range.output[0] === 'string') {
     return Globals.interpolation(range as InterpolationConfig<string>)