Add tryCatch decoder

docs/modules/Decoder.ts.md

@@ -70,6 +70,8 @@ Added in v2.2.7
   - [WithRefine](#withrefine)
   - [WithUnion](#withunion)
   - [WithUnknownContainers](#withunknowncontainers)
+- [interop](#interop)
+  - [tryCatch](#trycatch)
 - [model](#model)
   - [Decoder (interface)](#decoder-interface)
 - [primitives](#primitives)
@@ -578,6 +580,20 @@ export declare const WithUnknownContainers: S.WithUnknownContainers2C<'io-ts/Dec
 
 Added in v2.2.8
 
+# interop
+
+## tryCatch
+
+Constructs a new `Decoder` from a function that might throw.
+
+**Signature**
+
+```ts
+export declare const tryCatch: <I, A>(f: (i: I) => A, id: string) => Decoder<I, A>
+```
+
+Added in v2.2.17
+
 # model
 
 ## Decoder (interface)

docs/modules/TaskDecoder.ts.md

@@ -71,6 +71,8 @@ Added in v2.2.7
   - [WithRefine](#withrefine)
   - [WithUnion](#withunion)
   - [WithUnknownContainers](#withunknowncontainers)
+- [interop](#interop)
+  - [tryCatch](#trycatch)
 - [model](#model)
   - [TaskDecoder (interface)](#taskdecoder-interface)
 - [primitives](#primitives)
@@ -594,6 +596,20 @@ export declare const WithUnknownContainers: S.WithUnknownContainers2C<'io-ts/Tas
 
 Added in v2.2.8
 
+# interop
+
+## tryCatch
+
+Constructs a new `Decoder` from a function that returns a `Promise`.
+
+**Signature**
+
+```ts
+export declare const tryCatch: <I, A>(f: (i: I) => Promise<A>, id: string) => TaskDecoder<I, A>
+```
+
+Added in v2.2.17
+
 # model
 
 ## TaskDecoder (interface)

dtslint/ts3.5/Decoder.ts

@@ -158,3 +158,10 @@ _.readonly(
     a: _.string
   })
 )
+
+//
+// tryCatch
+//
+
+// $ExpectType Decoder<string, number>
+_.tryCatch((a: string) => a.length, 'Length')

dtslint/ts3.5/TaskDecoder.ts

@@ -22,3 +22,10 @@ _.readonly(
     a: _.string
   })
 )
+
+//
+// tryCatch
+//
+
+// $ExpectType TaskDecoder<string, number>
+_.tryCatch(async (a: string) => a.length, 'Length')

src/Decoder.ts

@@ -380,6 +380,24 @@ export const lazy: <I, A>(id: string, f: () => Decoder<I, A>) => Decoder<I, A> =
  */
 export const readonly: <I, A>(decoder: Decoder<I, A>) => Decoder<I, Readonly<A>> = identity
 
+// -------------------------------------------------------------------------------------
+// interop
+// -------------------------------------------------------------------------------------
+
+/**
+ * Constructs a new `Decoder` from a function that might throw.
+ *
+ * @category interop
+ * @since 2.2.17
+ */
+export const tryCatch: <I, A>(f: (i: I) => A, id: string) => Decoder<I, A> = (f, id) => ({
+  decode: (i) =>
+    E.tryCatch(
+      () => f(i),
+      () => error(i, id)
+    )
+})
+
 // -------------------------------------------------------------------------------------
 // non-pipeables
 // -------------------------------------------------------------------------------------

src/TaskDecoder.ts

@@ -386,6 +386,24 @@ export const lazy: <I, A>(id: string, f: () => TaskDecoder<I, A>) => TaskDecoder
  */
 export const readonly: <I, A>(decoder: TaskDecoder<I, A>) => TaskDecoder<I, Readonly<A>> = identity
 
+// -------------------------------------------------------------------------------------
+// interop
+// -------------------------------------------------------------------------------------
+
+/**
+ * Constructs a new `Decoder` from a function that returns a `Promise`.
+ *
+ * @category interop
+ * @since 2.2.17
+ */
+export const tryCatch: <I, A>(f: (i: I) => Promise<A>, id: string) => TaskDecoder<I, A> = (f, id) => ({
+  decode: (i) =>
+    TE.tryCatch(
+      () => f(i),
+      () => error(i, id)
+    )
+})
+
 // -------------------------------------------------------------------------------------
 // non-pipeables
 // -------------------------------------------------------------------------------------

test/Decoder.ts

@@ -529,6 +529,26 @@ describe('Decoder', () => {
     })
   })
 
+  // -------------------------------------------------------------------------------------
+  // interop
+  // -------------------------------------------------------------------------------------
+
+  describe('tryCatch', () => {
+    it('should decode when the function returns a value', () => {
+      const f = (value: number) => value + 1
+
+      assert.deepStrictEqual(_.tryCatch(f, 'Number').decode(1), _.success(2))
+    })
+
+    it('should reject when the function throws', () => {
+      const f = () => {
+        throw new Error('Some error')
+      }
+
+      assert.deepStrictEqual(_.tryCatch(f, 'Number').decode(1), E.left(FS.of(DE.leaf(1, 'Number'))))
+    })
+  })
+
   // -------------------------------------------------------------------------------------
   // utils
   // -------------------------------------------------------------------------------------

test/TaskDecoder.ts

@@ -575,6 +575,26 @@ describe('UnknownTaskDecoder', () => {
     })
   })
 
+  // -------------------------------------------------------------------------------------
+  // interop
+  // -------------------------------------------------------------------------------------
+
+  describe('tryCatch', () => {
+    it('should decode when the promise resolves with a value', async () => {
+      const f = async (value: number) => value + 1
+
+      assert.deepStrictEqual(await _.tryCatch(f, 'Number').decode(1)(), D.success(2))
+    })
+
+    it('should reject when the promise rejects', async () => {
+      const f = async () => {
+        throw new Error('Some error')
+      }
+
+      assert.deepStrictEqual(await _.tryCatch(f, 'Number').decode(1)(), E.left(FS.of(DE.leaf(1, 'Number'))))
+    })
+  })
+
   // -------------------------------------------------------------------------------------
   // utils
   // -------------------------------------------------------------------------------------