chore(parser): fix type inference for result types (aws-powertools#3293)

am29d · dreamorosi · web-flow · commit 112b4bbfb0fd · 2024-11-07T16:30:26.000+01:00
Co-authored-by: Andrea Amorosi &lt;dreamorosi@gmail.com&gt;
diff --git a/packages/parser/src/envelopes/apigw.ts b/packages/parser/src/envelopes/apigw.ts
@@ -2,17 +2,25 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { APIGatewayProxyEventSchema } from '../schemas/apigw.js';
 import type { ParsedResult } from '../types/parser.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * API Gateway envelope to extract data within body key
  */
 export const ApiGatewayEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'object' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T> {
     return Envelope.parse(APIGatewayProxyEventSchema.parse(data).body, schema);
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>> {
     const parsedEnvelope = APIGatewayProxyEventSchema.safeParse(data);
     if (!parsedEnvelope.success) {
       return {
diff --git a/packages/parser/src/envelopes/apigwv2.ts b/packages/parser/src/envelopes/apigwv2.ts
@@ -2,20 +2,28 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { APIGatewayProxyEventV2Schema } from '../schemas/apigwv2.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * API Gateway V2 envelope to extract data within body key
  */
 export const ApiGatewayV2Envelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'object' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T> {
     return Envelope.parse(
       APIGatewayProxyEventV2Schema.parse(data).body,
       schema
     );
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>> {
     const parsedEnvelope = APIGatewayProxyEventV2Schema.safeParse(data);
     if (!parsedEnvelope.success) {
       return {
diff --git a/packages/parser/src/envelopes/cloudwatch.ts b/packages/parser/src/envelopes/cloudwatch.ts
@@ -2,7 +2,7 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { CloudWatchLogsSchema } from '../schemas/index.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * CloudWatch Envelope to extract a List of log records.
@@ -14,6 +14,11 @@ import { Envelope } from './envelope.js';
  *  Note: The record will be parsed the same way so if model is str
  */
 export const CloudWatchEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'array' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T>[] {
     const parsedEnvelope = CloudWatchLogsSchema.parse(data);
 
@@ -22,7 +27,10 @@ export const CloudWatchEnvelope = {
     });
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>[]> {
     const parsedEnvelope = CloudWatchLogsSchema.safeParse(data);
 
     if (!parsedEnvelope.success) {
diff --git a/packages/parser/src/envelopes/dynamodb.ts b/packages/parser/src/envelopes/dynamodb.ts
@@ -3,7 +3,7 @@ import { ParseError } from '../errors.js';
 import { DynamoDBStreamSchema } from '../schemas/index.js';
 import type { DynamoDBStreamEnvelopeResponse } from '../types/envelope.js';
 import type { ParsedResult, ParsedResultError } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * DynamoDB Stream Envelope to extract data within NewImage/OldImage
@@ -12,6 +12,11 @@ import { Envelope } from './envelope.js';
  * length of the list is the record's amount in the original event.
  */
 export const DynamoDBStreamEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'array' as const,
   parse<T extends ZodSchema>(
     data: unknown,
     schema: T
@@ -26,7 +31,10 @@ export const DynamoDBStreamEnvelope = {
     });
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, DynamoDBStreamEnvelopeResponse<z.infer<T>>[]> {
     const parsedEnvelope = DynamoDBStreamSchema.safeParse(data);
 
     if (!parsedEnvelope.success) {
diff --git a/packages/parser/src/envelopes/envelope.ts b/packages/parser/src/envelopes/envelope.ts
@@ -2,7 +2,7 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import type { ParsedResult } from '../types/parser.js';
 
-export const Envelope = {
+const Envelope = {
   /**
    * Abstract function to parse the content of the envelope using provided schema.
    * Both inputs are provided as unknown by the user.
@@ -67,3 +67,11 @@ export const Envelope = {
     }
   },
 };
+
+/**
+ * This is a discriminator to differentiate whether an envelope returns an array or an object
+ * @hidden
+ */
+const envelopeDiscriminator = Symbol.for('returnType');
+
+export { Envelope, envelopeDiscriminator };
diff --git a/packages/parser/src/envelopes/event-bridge.ts b/packages/parser/src/envelopes/event-bridge.ts
@@ -2,12 +2,17 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { EventBridgeSchema } from '../schemas/index.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * Envelope for EventBridge schema that extracts and parses data from the `detail` key.
  */
 export const EventBridgeEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'object' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T> {
     return Envelope.parse(EventBridgeSchema.parse(data).detail, schema);
   },
diff --git a/packages/parser/src/envelopes/kafka.ts b/packages/parser/src/envelopes/kafka.ts
@@ -5,7 +5,7 @@ import {
   KafkaSelfManagedEventSchema,
 } from '../schemas/kafka.js';
 import type { KafkaMskEvent, ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * Kafka event envelope to extract data within body key
@@ -17,6 +17,11 @@ import { Envelope } from './envelope.js';
  */
 
 export const KafkaEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'array' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T>[] {
     // manually fetch event source to decide between Msk or SelfManaged
     const eventSource = (data as KafkaMskEvent).eventSource;
@@ -35,7 +40,10 @@ export const KafkaEnvelope = {
     });
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>[]> {
     // manually fetch event source to deside between Msk or SelfManaged
     const eventSource = (data as KafkaMskEvent).eventSource;
 
diff --git a/packages/parser/src/envelopes/kinesis-firehose.ts b/packages/parser/src/envelopes/kinesis-firehose.ts
@@ -2,7 +2,7 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { KinesisFirehoseSchema } from '../schemas/index.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * Kinesis Firehose Envelope to extract array of Records
@@ -17,6 +17,11 @@ import { Envelope } from './envelope.js';
  *  https://docs.aws.amazon.com/lambda/latest/dg/services-kinesisfirehose.html
  */
 export const KinesisFirehoseEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'array' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T>[] {
     const parsedEnvelope = KinesisFirehoseSchema.parse(data);
 
@@ -25,7 +30,10 @@ export const KinesisFirehoseEnvelope = {
     });
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>[]> {
     const parsedEnvelope = KinesisFirehoseSchema.safeParse(data);
 
     if (!parsedEnvelope.success) {
diff --git a/packages/parser/src/envelopes/kinesis.ts b/packages/parser/src/envelopes/kinesis.ts
@@ -2,7 +2,7 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { KinesisDataStreamSchema } from '../schemas/kinesis.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * Kinesis Data Stream Envelope to extract array of Records
@@ -15,6 +15,11 @@ import { Envelope } from './envelope.js';
  * all items in the list will be parsed as str and not as JSON (and vice versa)
  */
 export const KinesisEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'array' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T>[] {
     const parsedEnvelope = KinesisDataStreamSchema.parse(data);
 
@@ -23,7 +28,10 @@ export const KinesisEnvelope = {
     });
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>[]> {
     const parsedEnvelope = KinesisDataStreamSchema.safeParse(data);
     if (!parsedEnvelope.success) {
       return {
diff --git a/packages/parser/src/envelopes/lambda.ts b/packages/parser/src/envelopes/lambda.ts
@@ -2,12 +2,17 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { LambdaFunctionUrlSchema } from '../schemas/index.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * Lambda function URL envelope to extract data within body key
  */
 export const LambdaFunctionUrlEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'object' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T> {
     const parsedEnvelope = LambdaFunctionUrlSchema.parse(data);
 
diff --git a/packages/parser/src/envelopes/sns.ts b/packages/parser/src/envelopes/sns.ts
@@ -3,7 +3,7 @@ import { ParseError } from '../errors.js';
 import { SnsSchema, SnsSqsNotificationSchema } from '../schemas/sns.js';
 import { SqsSchema } from '../schemas/sqs.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * SNS Envelope to extract array of Records
@@ -15,6 +15,11 @@ import { Envelope } from './envelope.js';
  * all items in the list will be parsed as str and npt as JSON (and vice versa)
  */
 export const SnsEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'array' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T>[] {
     const parsedEnvelope = SnsSchema.parse(data);
 
@@ -23,7 +28,10 @@ export const SnsEnvelope = {
     });
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>[]> {
     const parsedEnvelope = SnsSchema.safeParse(data);
 
     if (!parsedEnvelope.success) {
@@ -70,7 +78,12 @@ export const SnsEnvelope = {
  *
  */
 export const SnsSqsEnvelope = {
-  parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T> {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'array' as const,
+  parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T>[] {
     const parsedEnvelope = SqsSchema.parse(data);
 
     return parsedEnvelope.Records.map((record) => {
@@ -82,7 +95,10 @@ export const SnsSqsEnvelope = {
     });
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>[]> {
     const parsedEnvelope = SqsSchema.safeParse(data);
     if (!parsedEnvelope.success) {
       return {
diff --git a/packages/parser/src/envelopes/sqs.ts b/packages/parser/src/envelopes/sqs.ts
@@ -2,7 +2,7 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { SqsSchema } from '../schemas/sqs.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  *  SQS Envelope to extract array of Records
@@ -14,6 +14,11 @@ import { Envelope } from './envelope.js';
  *  all items in the list will be parsed as str and npt as JSON (and vice versa)
  */
 export const SqsEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'array' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T>[] {
     const parsedEnvelope = SqsSchema.parse(data);
 
@@ -22,7 +27,10 @@ export const SqsEnvelope = {
     });
   },
 
-  safeParse<T extends ZodSchema>(data: unknown, schema: T): ParsedResult {
+  safeParse<T extends ZodSchema>(
+    data: unknown,
+    schema: T
+  ): ParsedResult<unknown, z.infer<T>[]> {
     const parsedEnvelope = SqsSchema.safeParse(data);
     if (!parsedEnvelope.success) {
       return {
diff --git a/packages/parser/src/envelopes/vpc-lattice.ts b/packages/parser/src/envelopes/vpc-lattice.ts
@@ -2,13 +2,18 @@ import type { ZodSchema, z } from 'zod';
 import { ParseError } from '../errors.js';
 import { VpcLatticeSchema } from '../schemas/index.js';
 import type { ParsedResult } from '../types/index.js';
-import { Envelope } from './envelope.js';
+import { Envelope, envelopeDiscriminator } from './envelope.js';
 
 /**
  * Amazon VPC Lattice envelope to extract data within body key
  */
 
 export const VpcLatticeEnvelope = {
+  /**
+   * This is a discriminator to differentiate whether an envelope returns an array or an object
+   * @hidden
+   */
+  [envelopeDiscriminator]: 'object' as const,
   parse<T extends ZodSchema>(data: unknown, schema: T): z.infer<T> {
     const parsedEnvelope = VpcLatticeSchema.parse(data);
 
diff --git a/packages/parser/src/envelopes/vpc-latticev2.ts b/packages/parser/src/envelopes/vpc-latticev2.ts
diff --git a/packages/parser/src/middleware/parser.ts b/packages/parser/src/middleware/parser.ts
diff --git a/packages/parser/src/types/envelope.ts b/packages/parser/src/types/envelope.ts
diff --git a/packages/parser/src/types/parser.ts b/packages/parser/src/types/parser.ts
diff --git a/packages/parser/tests/unit/types.test.ts b/packages/parser/tests/unit/types.test.ts
