feat: export "inferTo" function

and the InferTo type.

Author: aleclarson

packages/core/src/Controller.ts

@@ -21,7 +21,7 @@ import {
 import { Indexable, Falsy } from './types/common'
 import { runAsync, scheduleProps, RunAsyncState, AsyncResult } from './runAsync'
 import { SpringPhase, CREATED, ACTIVE, IDLE } from './SpringPhase'
-import { interpolateTo } from './helpers'
+import { inferTo } from './helpers'
 import { SpringValue } from './SpringValue'
 import { FrameValue } from './FrameValue'
 
@@ -103,7 +103,7 @@ export class Controller<State extends Indexable = UnknownProps>
   constructor(props?: ControllerProps<State>) {
     this._onFrame = this._onFrame.bind(this)
     if (props) {
-      const { to, ...initialProps } = interpolateTo(props as any)
+      const { to, ...initialProps } = inferTo(props as any)
       this._initialProps = initialProps
       if (to) this.start({ to })
     }
@@ -261,7 +261,7 @@ export class Controller<State extends Indexable = UnknownProps>
 
   /** Prepare an update with the given props. */
   protected _prepareUpdate(propsArg: ControllerProps<State>) {
-    const props: PendingProps<State> = interpolateTo(propsArg) as any
+    const props: PendingProps<State> = inferTo(propsArg) as any
     let { from, to } = props as any
 
     // Avoid sending async "to" prop to springs.

packages/core/src/helpers.test.ts

@@ -1,4 +1,4 @@
-import { interpolateTo } from './helpers'
+import { inferTo } from './helpers'
 import { ReservedProps } from './types/common'
 
 describe('helpers', () => {
@@ -38,7 +38,7 @@ describe('helpers', () => {
       onRest: undefined,
     }
     expect(
-      interpolateTo({
+      inferTo({
         ...forwardProps,
         ...restProps,
         ...excludeProps,

packages/core/src/helpers.ts

@@ -108,12 +108,19 @@ function getForwardProps<Props extends ReservedProps>(
   return forward
 }
 
-export type InterpolateTo<T extends object> = Merge<
+/**
+ * Move all non-reserved props into the `to` prop.
+ */
+export type InferTo<T extends object> = Merge<
   { to: ForwardProps<T> },
   Pick<T, keyof T & keyof ReservedProps>
 >
 
-export function interpolateTo<T extends object>(props: T): InterpolateTo<T> {
+/**
+ * Clone the given `props` and move all non-reserved props
+ * into the `to` prop.
+ */
+export function inferTo<T extends object>(props: T): InferTo<T> {
   const to = getForwardProps(props)
   const out: any = { to }
   each(props, (val, key) => key in to || (out[key] = val))

packages/core/src/index.ts

@@ -36,6 +36,7 @@ export {
   UnknownProps,
 } from './types/common'
 
+export { inferTo, InferTo } from './helpers'
 export { FrameLoop, Animatable, createInterpolator } from 'shared'
 
 export * from 'shared/types/animated'

packages/core/src/useTransition.tsx

@@ -19,7 +19,7 @@ import {
 } from 'shared'
 import { now } from 'shared/globals'
 
-import { DEFAULT_PROPS, callProp, interpolateTo } from './helpers'
+import { DEFAULT_PROPS, callProp, inferTo } from './helpers'
 import { SpringHandle, AsyncTo, FromProp, SpringValues } from './types/spring'
 import { Controller, ControllerProps } from './Controller'
 import { AnimationProps, AnimationEvents } from './types/animated'
@@ -244,7 +244,7 @@ export function useTransition(
       from: callProp(from, t.item, i),
       delay: delay += trail,
       config: callProp(props.config || defaultProps.config, t.item, i),
-      ...(is.obj(to) && interpolateTo(to)),
+      ...(is.obj(to) && inferTo(to)),
     }
 
     const { onRest } = payload