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effect

Differ overview

Added in v2.0.0

Table of contents

constructors

chunk

Constructs a differ that knows how to diff a Chunk of values given a differ that knows how to diff the values.

Signature

export declare const chunk: <Value, Patch>(
  differ: Differ<Value, Patch>
) => Differ<Chunk<Value>, Differ.Chunk.Patch<Value, Patch>>

Added in v2.0.0

environment

Constructs a differ that knows how to diff Env values.

Signature

export declare const environment: <A>() => Differ<Context<A>, Differ.Context.Patch<A, A>>

Added in v2.0.0

hashMap

Constructs a differ that knows how to diff a HashMap of keys and values given a differ that knows how to diff the values.

Signature

export declare const hashMap: <Key, Value, Patch>(
  differ: Differ<Value, Patch>
) => Differ<HashMap<Key, Value>, Differ.HashMap.Patch<Key, Value, Patch>>

Added in v2.0.0

hashSet

Constructs a differ that knows how to diff a HashSet of values.

Signature

export declare const hashSet: <Value>() => Differ<HashSet<Value>, Differ.HashSet.Patch<Value>>

Added in v2.0.0

make

Constructs a new Differ.

Signature

export declare const make: <Value, Patch>(params: {
  readonly empty: Patch
  readonly diff: (oldValue: Value, newValue: Value) => Patch
  readonly combine: (first: Patch, second: Patch) => Patch
  readonly patch: (patch: Patch, oldValue: Value) => Value
}) => Differ<Value, Patch>

Added in v2.0.0

readonlyArray

Constructs a differ that knows how to diff a ReadonlyArray of values.

Signature

export declare const readonlyArray: <Value, Patch>(
  differ: Differ<Value, Patch>
) => Differ<readonly Value[], Differ.ReadonlyArray.Patch<Value, Patch>>

Added in v2.0.0

models

Differ (interface)

A Differ<Value, Patch> knows how to compare an old value and new value of type Value to produce a patch of type Patch that describes the differences between those values. A Differ also knows how to apply a patch to an old value to produce a new value that represents the old value updated with the changes described by the patch.

A Differ can be used to construct a FiberRef supporting compositional updates using the FiberRef.makePatch constructor.

The Differ companion object contains constructors for Differ values for common data types such as Chunk, HashMap, and HashSet. In addition, Differvalues can be transformed using the transformoperator and combined using theorElseEitherandzipoperators. This allows creatingDiffer` values for arbitrarily complex data types compositionally.

Signature

export interface Differ<in out Value, in out Patch> {
  readonly [TypeId]: {
    readonly _V: Types.Invariant<Value>
    readonly _P: Types.Invariant<Patch>
  }
  readonly empty: Patch
  diff(oldValue: Value, newValue: Value): Patch
  combine(first: Patch, second: Patch): Patch
  patch(patch: Patch, oldValue: Value): Value
}

Added in v2.0.0

patch

combine

Combines two patches to produce a new patch that describes the updates of the first patch and then the updates of the second patch. The combine operation should be associative. In addition, if the combine operation is commutative then joining multiple fibers concurrently will result in deterministic FiberRef values.

Signature

export declare const combine: {
  <Patch>(first: Patch, second: Patch): <Value>(self: Differ<Value, Patch>) => Patch
  <Value, Patch>(self: Differ<Value, Patch>, first: Patch, second: Patch): Patch
}

Added in v2.0.0

diff

Signature

export declare const diff: {
  <Value>(oldValue: Value, newValue: Value): <Patch>(self: Differ<Value, Patch>) => Patch
  <Value, Patch>(self: Differ<Value, Patch>, oldValue: Value, newValue: Value): Patch
}

Added in v2.0.0

empty

An empty patch that describes no changes.

Signature

export declare const empty: <Value, Patch>(self: Differ<Value, Patch>) => Patch

Added in v2.0.0

patch

Applies a patch to an old value to produce a new value that is equal to the old value with the updates described by the patch.

Signature

export declare const patch: {
  <Patch, Value>(patch: Patch, oldValue: Value): (self: Differ<Value, Patch>) => Value
  <Patch, Value>(self: Differ<Value, Patch>, patch: Patch, oldValue: Value): Value
}

Added in v2.0.0

symbol

TypeId

Signature

export declare const TypeId: typeof TypeId

Added in v2.0.0

TypeId (type alias)

Signature

export type TypeId = typeof TypeId

Added in v2.0.0

utils

Differ (namespace)

Added in v2.0.0

Chunk (namespace)

Added in v2.0.0

Patch (interface)

A patch which describes updates to a chunk of values.

Signature

export interface Patch<in out Value, in out Patch> extends Equal {
  readonly [ChunkPatchTypeId]: {
    readonly _Value: Types.Invariant<Value>
    readonly _Patch: Types.Invariant<Patch>
  }
}

Added in v2.0.0

TypeId (type alias)

Signature

export type TypeId = typeof ChunkPatchTypeId

Added in v2.0.0

Context (namespace)

Added in v2.0.0

Patch (interface)

A Patch<Input, Output> describes an update that transforms a Env<Input> to a Env<Output> as a data structure. This allows combining updates to different services in the environment in a compositional way.

Signature

export interface Patch<in Input, out Output> extends Equal {
  readonly [ContextPatchTypeId]: {
    readonly _Input: Types.Contravariant<Input>
    readonly _Output: Types.Covariant<Output>
  }
}

Added in v2.0.0

TypeId (type alias)

Signature

export type TypeId = typeof ContextPatchTypeId

Added in v2.0.0

HashMap (namespace)

Added in v2.0.0

Patch (interface)

A patch which describes updates to a map of keys and values.

Signature

export interface Patch<in out Key, in out Value, in out Patch> extends Equal {
  readonly [HashMapPatchTypeId]: {
    readonly _Key: Types.Invariant<Key>
    readonly _Value: Types.Invariant<Value>
    readonly _Patch: Types.Invariant<Patch>
  }
}

Added in v2.0.0

TypeId (type alias)

Signature

export type TypeId = typeof HashMapPatchTypeId

Added in v2.0.0

HashSet (namespace)

Added in v2.0.0

Patch (interface)

A patch which describes updates to a set of values.

Signature

export interface Patch<in out Value> extends Equal {
  readonly [HashSetPatchTypeId]: {
    readonly _Value: Types.Invariant<Value>
  }
}

Added in v2.0.0

TypeId (type alias)

Signature

export type TypeId = typeof HashSetPatchTypeId

Added in v2.0.0

Or (namespace)

Added in v2.0.0

Patch (interface)

A patch which describes updates to either one value or another.

Signature

export interface Patch<in out Value, in out Value2, in out Patch, in out Patch2> extends Equal {
  readonly [OrPatchTypeId]: {
    readonly _Value: Types.Invariant<Value>
    readonly _Value2: Types.Invariant<Value2>
    readonly _Patch: Types.Invariant<Patch>
    readonly _Patch2: Types.Invariant<Patch2>
  }
}

Added in v2.0.0

TypeId (type alias)

Signature

export type TypeId = typeof OrPatchTypeId

Added in v2.0.0

ReadonlyArray (namespace)

Added in v2.0.0

Patch (interface)

A patch which describes updates to a ReadonlyArray of values.

Signature

export interface Patch<in out Value, in out Patch> extends Equal {
  readonly [ReadonlyArrayPatchTypeId]: {
    readonly _Value: Types.Invariant<Value>
    readonly _Patch: Types.Invariant<Patch>
  }
}

Added in v2.0.0

TypeId (type alias)

Signature

export type TypeId = typeof ReadonlyArrayPatchTypeId

Added in v2.0.0

orElseEither

Combines this differ and the specified differ to produce a differ that knows how to diff the sum of their values.

Signature

export declare const orElseEither: {
  <Value2, Patch2>(
    that: Differ<Value2, Patch2>
  ): <Value, Patch>(
    self: Differ<Value, Patch>
  ) => Differ<Either<Value2, Value>, Differ.Or.Patch<Value, Value2, Patch, Patch2>>
  <Value, Patch, Value2, Patch2>(
    self: Differ<Value, Patch>,
    that: Differ<Value2, Patch2>
  ): Differ<Either<Value2, Value>, Differ.Or.Patch<Value, Value2, Patch, Patch2>>
}

Added in v2.0.0

transform

Transforms the type of values that this differ knows how to differ using the specified functions that map the new and old value types to each other.

Signature

export declare const transform: {
  <Value, Value2>(options: {
    readonly toNew: (value: Value) => Value2
    readonly toOld: (value: Value2) => Value
  }): <Patch>(self: Differ<Value, Patch>) => Differ<Value2, Patch>
  <Value, Patch, Value2>(
    self: Differ<Value, Patch>,
    options: { readonly toNew: (value: Value) => Value2; readonly toOld: (value: Value2) => Value }
  ): Differ<Value2, Patch>
}

Added in v2.0.0

update

Constructs a differ that just diffs two values by returning a function that sets the value to the new value. This differ does not support combining multiple updates to the value compositionally and should only be used when there is no compositional way to update them.

Signature

export declare const update: <A>() => Differ<A, (a: A) => A>

Added in v2.0.0

updateWith

A variant of update that allows specifying the function that will be used to combine old values with new values.

Signature

export declare const updateWith: <A>(f: (x: A, y: A) => A) => Differ<A, (a: A) => A>

Added in v2.0.0

zip

Combines this differ and the specified differ to produce a new differ that knows how to diff the product of their values.

Signature

export declare const zip: {
  <Value2, Patch2>(
    that: Differ<Value2, Patch2>
  ): <Value, Patch>(self: Differ<Value, Patch>) => Differ<readonly [Value, Value2], readonly [Patch, Patch2]>
  <Value, Patch, Value2, Patch2>(
    self: Differ<Value, Patch>,
    that: Differ<Value2, Patch2>
  ): Differ<readonly [Value, Value2], readonly [Patch, Patch2]>
}

Added in v2.0.0