Add propertyOrder option to ParseOptions to control the order of … (

#2926)

.changeset/pretty-yaks-peel.md

@@ -0,0 +1,73 @@
+---
+"@effect/schema": patch
+---
+
+Add `propertyOrder` option to `ParseOptions` to control the order of keys in the output, closes #2925.
+
+The `propertyOrder` option provides control over the order of object fields in the output. This feature is particularly useful when the sequence of keys is important for the consuming processes or when maintaining the input order enhances readability and usability.
+
+By default, the `propertyOrder` option is set to `"none"`. This means that the internal system decides the order of keys to optimize parsing speed. The order of keys in this mode should not be considered stable, and it's recommended not to rely on key ordering as it may change in future updates without notice.
+
+Setting `propertyOrder` to `"input"` ensures that the keys are ordered as they appear in the input during the decoding/encoding process.
+
+**Example** (Synchronous Decoding)
+
+```ts
+import { Schema } from "@effect/schema"
+
+const schema = Schema.Struct({
+  a: Schema.Number,
+  b: Schema.Literal("b"),
+  c: Schema.Number
+})
+
+// Decoding an object synchronously without specifying the property order
+console.log(Schema.decodeUnknownSync(schema)({ b: "b", c: 2, a: 1 }))
+// Output decided internally: { b: 'b', a: 1, c: 2 }
+
+// Decoding an object synchronously while preserving the order of properties as in the input
+console.log(
+  Schema.decodeUnknownSync(schema)(
+    { b: "b", c: 2, a: 1 },
+    { propertyOrder: "original" }
+  )
+)
+// Output preserving input order: { b: 'b', c: 2, a: 1 }
+```
+
+**Example** (Asynchronous Decoding)
+
+```ts
+import { ParseResult, Schema } from "@effect/schema"
+import type { Duration } from "effect"
+import { Effect } from "effect"
+
+// Function to simulate an asynchronous process within the schema
+const effectify = (duration: Duration.DurationInput) =>
+  Schema.Number.pipe(
+    Schema.transformOrFail(Schema.Number, {
+      decode: (x) =>
+        Effect.sleep(duration).pipe(Effect.andThen(ParseResult.succeed(x))),
+      encode: ParseResult.succeed
+    })
+  )
+
+// Define a structure with asynchronous behavior in each field
+const schema = Schema.Struct({
+  a: effectify("200 millis"),
+  b: effectify("300 millis"),
+  c: effectify("100 millis")
+}).annotations({ concurrency: 3 })
+
+// Decoding data asynchronously without preserving order
+Schema.decode(schema)({ a: 1, b: 2, c: 3 })
+  .pipe(Effect.runPromise)
+  .then(console.log)
+// Output decided internally: { c: 3, a: 1, b: 2 }
+
+// Decoding data asynchronously while preserving the original input order
+Schema.decode(schema)({ a: 1, b: 2, c: 3 }, { propertyOrder: "original" })
+  .pipe(Effect.runPromise)
+  .then(console.log)
+// Output preserving input order: { a: 1, b: 2, c: 3 }
+```

packages/schema/README.md

@@ -611,6 +611,76 @@ Error: { readonly name: string; readonly age: number }
 > [!NOTE]
 > The [`onExcessProperty`](#excess-properties) and [`error`](#all-errors) options also affect encoding.
 
+### Managing Property Order
+
+The `propertyOrder` option provides control over the order of object fields in the output. This feature is particularly useful when the sequence of keys is important for the consuming processes or when maintaining the input order enhances readability and usability.
+
+By default, the `propertyOrder` option is set to `"none"`. This means that the internal system decides the order of keys to optimize parsing speed. The order of keys in this mode should not be considered stable, and it's recommended not to rely on key ordering as it may change in future updates without notice.
+
+Setting `propertyOrder` to `"input"` ensures that the keys are ordered as they appear in the input during the decoding/encoding process.
+
+**Example** (Synchronous Decoding)
+
+```ts
+import { Schema } from "@effect/schema"
+
+const schema = Schema.Struct({
+  a: Schema.Number,
+  b: Schema.Literal("b"),
+  c: Schema.Number
+})
+
+// Decoding an object synchronously without specifying the property order
+console.log(Schema.decodeUnknownSync(schema)({ b: "b", c: 2, a: 1 }))
+// Output decided internally: { b: 'b', a: 1, c: 2 }
+
+// Decoding an object synchronously while preserving the order of properties as in the input
+console.log(
+  Schema.decodeUnknownSync(schema)(
+    { b: "b", c: 2, a: 1 },
+    { propertyOrder: "original" }
+  )
+)
+// Output preserving input order: { b: 'b', c: 2, a: 1 }
+```
+
+**Example** (Asynchronous Decoding)
+
+```ts
+import { ParseResult, Schema } from "@effect/schema"
+import type { Duration } from "effect"
+import { Effect } from "effect"
+
+// Function to simulate an asynchronous process within the schema
+const effectify = (duration: Duration.DurationInput) =>
+  Schema.Number.pipe(
+    Schema.transformOrFail(Schema.Number, {
+      decode: (x) =>
+        Effect.sleep(duration).pipe(Effect.andThen(ParseResult.succeed(x))),
+      encode: ParseResult.succeed
+    })
+  )
+
+// Define a structure with asynchronous behavior in each field
+const schema = Schema.Struct({
+  a: effectify("200 millis"),
+  b: effectify("300 millis"),
+  c: effectify("100 millis")
+}).annotations({ concurrency: 3 })
+
+// Decoding data asynchronously without preserving order
+Schema.decode(schema)({ a: 1, b: 2, c: 3 })
+  .pipe(Effect.runPromise)
+  .then(console.log)
+// Output decided internally: { c: 3, a: 1, b: 2 }
+
+// Decoding data asynchronously while preserving the original input order
+Schema.decode(schema)({ a: 1, b: 2, c: 3 }, { propertyOrder: "original" })
+  .pipe(Effect.runPromise)
+  .then(console.log)
+// Output preserving input order: { a: 1, b: 2, c: 3 }
+```
+
 ## Encoding
 
 The `@effect/schema/Schema` module provides several `encode*` functions to encode data according to a schema:

packages/schema/benchmark/preserveKeyOrder.ts

@@ -0,0 +1,49 @@
+import * as ParseResult from "@effect/schema/ParseResult"
+import * as S from "@effect/schema/Schema"
+import { Bench } from "tinybench"
+
+/*
+┌─────────┬────────────────────────────────────────────────────────────┬──────────────┬────────────────────┬──────────┬──────────┐
+│ (index) │                         Task Name                          │   ops/sec    │ Average Time (ns)  │  Margin  │ Samples  │
+├─────────┼────────────────────────────────────────────────────────────┼──────────────┼────────────────────┼──────────┼──────────┤
+│    0    │            'decodeUnknownEither (valid input)'             │ '1,249,635'  │ 800.2333527737999  │ '±0.30%' │ 1249636  │
+│    1    │  'decodeUnknownEitherPreserveInputKeyOrder (valid input)'  │  '853,288'   │ 1171.9369854943957 │ '±0.17%' │  853289  │
+│    2    │           'decodeUnknownEither (invalid input)'            │ '11,534,459' │ 86.69673906736591  │ '±0.31%' │ 11534460 │
+│    3    │ 'decodeUnknownEitherPreserveInputKeyOrder (invalid input)' │ '11,435,077' │ 87.45021734921293  │ '±0.34%' │ 11435078 │
+└─────────┴────────────────────────────────────────────────────────────┴──────────────┴────────────────────┴──────────┴──────────┘
+*/
+
+const bench = new Bench({ time: 1000 })
+
+const schema = S.Struct({
+  a: S.Literal("a"),
+  b: S.Array(S.String),
+  c: S.Record(S.String, S.Number),
+  d: S.NumberFromString,
+  e: S.Boolean
+})
+
+const validInput = { a: "a", b: ["b"], c: { c: 1 }, d: "1", e: true }
+
+const invalidInput = { b: ["b"], c: { c: 1 }, d: "1", e: true, a: null }
+
+const decodeUnknownEither = ParseResult.decodeUnknownEither(schema)
+const decodeUnknownEitherPreserveInputKeyOrder = ParseResult.decodeUnknownEither(schema, { propertyOrder: "original" })
+
+bench
+  .add("decodeUnknownEither (valid input)", function() {
+    decodeUnknownEither(validInput)
+  })
+  .add("decodeUnknownEitherPreserveInputKeyOrder (valid input)", function() {
+    decodeUnknownEitherPreserveInputKeyOrder(validInput)
+  })
+  .add("decodeUnknownEither (invalid input)", function() {
+    decodeUnknownEither(invalidInput)
+  })
+  .add("decodeUnknownEitherPreserveInputKeyOrder (invalid input)", function() {
+    decodeUnknownEitherPreserveInputKeyOrder(invalidInput)
+  })
+
+await bench.run()
+
+console.table(bench.table())

packages/schema/src/AST.ts

@@ -1640,6 +1640,12 @@ export interface ParseOptions {
   readonly errors?: "first" | "all" | undefined
   /** default "ignore" */
   readonly onExcessProperty?: "ignore" | "error" | "preserve" | undefined
+  /**
+   * default "none"
+   *
+   * @since 0.67.20
+   */
+  readonly propertyOrder?: "none" | "original" | undefined
 }
 
 /**

packages/schema/src/ParseResult.ts

@@ -1147,10 +1147,12 @@ const go = (ast: AST.AST, isDecoding: boolean): Parser => {
       }
 
       const propertySignatures: Array<readonly [Parser, AST.PropertySignature]> = []
-      const expectedKeys: Record<PropertyKey, null> = {}
+      const expectedKeysMap: Record<PropertyKey, null> = {}
+      const expectedKeys: Array<PropertyKey> = []
       for (const ps of ast.propertySignatures) {
         propertySignatures.push([goMemo(ps.type, isDecoding), ps])
-        expectedKeys[ps.name] = null
+        expectedKeysMap[ps.name] = null
+        expectedKeys.push(ps.name)
       }
 
       const indexSignatures = ast.indexSignatures.map((is) =>
@@ -1162,9 +1164,7 @@ const go = (ast: AST.AST, isDecoding: boolean): Parser => {
       )
       const expectedAST = AST.Union.make(
         ast.indexSignatures.map((is): AST.AST => is.parameter).concat(
-          util_.ownKeys(expectedKeys).map((key) =>
-            Predicate.isSymbol(key) ? new AST.UniqueSymbol(key) : new AST.Literal(key)
-          )
+          expectedKeys.map((key) => Predicate.isSymbol(key) ? new AST.UniqueSymbol(key) : new AST.Literal(key))
         )
       )
       const expected = goMemo(expectedAST, isDecoding)
@@ -1184,8 +1184,10 @@ const go = (ast: AST.AST, isDecoding: boolean): Parser => {
         const onExcessPropertyError = options?.onExcessProperty === "error"
         const onExcessPropertyPreserve = options?.onExcessProperty === "preserve"
         const output: any = {}
+        let inputKeys: Array<PropertyKey> | undefined
         if (onExcessPropertyError || onExcessPropertyPreserve) {
-          for (const key of util_.ownKeys(input)) {
+          inputKeys = util_.ownKeys(input)
+          for (const key of inputKeys) {
             const eu = eitherOrUndefined(expected(key, options))!
             if (Either.isLeft(eu)) {
               // key is unexpected
@@ -1302,7 +1304,7 @@ const go = (ast: AST.AST, isDecoding: boolean): Parser => {
                     return Either.left(new TypeLiteral(ast, input, [e], output))
                   }
                 } else {
-                  if (!Object.prototype.hasOwnProperty.call(expectedKeys, key)) {
+                  if (!Object.prototype.hasOwnProperty.call(expectedKeysMap, key)) {
                     output[key] = veu.right
                   }
                 }
@@ -1326,7 +1328,7 @@ const go = (ast: AST.AST, isDecoding: boolean): Parser => {
                             return Either.left(new TypeLiteral(ast, input, [e], output))
                           }
                         } else {
-                          if (!Object.prototype.hasOwnProperty.call(expectedKeys, key)) {
+                          if (!Object.prototype.hasOwnProperty.call(expectedKeysMap, key)) {
                             output[key] = tv.right
                           }
                           return Effect.void
@@ -1341,10 +1343,26 @@ const go = (ast: AST.AST, isDecoding: boolean): Parser => {
         // ---------------------------------------------
         // compute result
         // ---------------------------------------------
-        const computeResult = ({ es, output }: State) =>
-          Arr.isNonEmptyArray(es) ?
-            Either.left(new TypeLiteral(ast, input, sortByIndex(es), output)) :
-            Either.right(output)
+        const computeResult = ({ es, output }: State) => {
+          if (Arr.isNonEmptyArray(es)) {
+            return Either.left(new TypeLiteral(ast, input, sortByIndex(es), output))
+          }
+          if (options?.propertyOrder === "original") {
+            // preserve input keys order
+            const keys = inputKeys || util_.ownKeys(input)
+            for (const name of expectedKeys) {
+              if (keys.indexOf(name) === -1) {
+                keys.push(name)
+              }
+            }
+            const out: any = {}
+            for (const key of keys) {
+              out[key] = output[key]
+            }
+            return Either.right(out)
+          }
+          return Either.right(output)
+        }
         if (queue && queue.length > 0) {
           const cqueue = queue
           return Effect.suspend(() => {

packages/schema/test/Schema/ParseOptions-preserveKeyOrder.test.ts

@@ -0,0 +1,71 @@
+import * as ParseResult from "@effect/schema/ParseResult"
+import * as S from "@effect/schema/Schema"
+import type { Duration } from "effect"
+import * as Effect from "effect/Effect"
+import { describe, expect, it } from "vitest"
+
+describe("`preserveKeyOrder` option", () => {
+  const b = Symbol.for("@effect/schema/test/b")
+  const Sync = S.Struct({
+    a: S.Literal("a"),
+    [b]: S.Array(S.String),
+    c: S.Record(S.String, S.Number),
+    d: S.NumberFromString,
+    e: S.Boolean,
+    f: S.optional(S.String)
+  })
+
+  const effectify = (duration: Duration.DurationInput) =>
+    S.NumberFromString.pipe(
+      S.transformOrFail(S.Number, {
+        decode: (x) => Effect.sleep(duration).pipe(Effect.andThen(ParseResult.succeed(x))),
+        encode: ParseResult.succeed
+      })
+    )
+
+  const Async = S.Struct({
+    a: effectify("20 millis"),
+    [b]: effectify("30 millis"),
+    c: effectify("10 millis")
+  }).annotations({ concurrency: 3 })
+
+  describe("decoding", () => {
+    it("should preserve the order of input properties (sync)", () => {
+      const input = { [b]: ["b"], c: { c: 1 }, d: "1", e: true, a: "a", other: 1 }
+      const output = S.decodeUnknownSync(Sync)(input, { propertyOrder: "original", onExcessProperty: "preserve" })
+      const expectedOutput = { [b]: ["b"], c: { c: 1 }, d: 1, e: true, a: "a", other: 1, f: undefined }
+      expect(output).toStrictEqual(expectedOutput)
+      expect(Reflect.ownKeys(output)).toStrictEqual(Reflect.ownKeys(expectedOutput))
+    })
+
+    it("should preserve the order of input properties (async)", async () => {
+      const input = { a: "1", c: "3", [b]: "2", other: 1 }
+      const output = await Effect.runPromise(
+        S.decodeUnknown(Async)(input, { propertyOrder: "original", onExcessProperty: "preserve" })
+      )
+      const expectedOutput = { a: 1, c: 3, [b]: 2, other: 1 }
+      expect(output).toStrictEqual(expectedOutput)
+      expect(Reflect.ownKeys(output)).toStrictEqual(Reflect.ownKeys(expectedOutput))
+    })
+  })
+
+  describe("encoding", () => {
+    it("should preserve the order of input properties (sync)", () => {
+      const input = { [b]: ["b"], c: { c: 1 }, d: 1, e: true, a: "a", other: 1 }
+      const output = S.encodeUnknownSync(Sync)(input, { propertyOrder: "original", onExcessProperty: "preserve" })
+      const expectedOutput = { [b]: ["b"], c: { c: 1 }, d: "1", e: true, a: "a", other: 1, f: undefined }
+      expect(output).toStrictEqual(expectedOutput)
+      expect(Reflect.ownKeys(output)).toStrictEqual(Reflect.ownKeys(expectedOutput))
+    })
+
+    it("should preserve the order of input properties (async)", async () => {
+      const input = { a: 1, c: 3, [b]: 2, other: 1 }
+      const output = await Effect.runPromise(
+        S.encodeUnknown(Async)(input, { propertyOrder: "original", onExcessProperty: "preserve" })
+      )
+      const expectedOutput = { a: "1", c: "3", [b]: "2", other: 1 }
+      expect(output).toStrictEqual(expectedOutput)
+      expect(Reflect.ownKeys(output)).toStrictEqual(Reflect.ownKeys(expectedOutput))
+    })
+  })
+})