Add json

docs/modules/Codec.ts.md

@@ -31,6 +31,7 @@ Added in v2.2.3
   - [fromSum](#fromsum)
   - [fromTuple](#fromtuple)
   - [intersect](#intersect)
+  - [json](#json)
   - [lazy](#lazy)
   - [mapLeftWithInput](#mapleftwithinput)
   - [nullable](#nullable)
@@ -194,6 +195,16 @@ export declare const intersect: <IB, OB, B>(
 
 Added in v2.2.3
 
+## json
+
+**Signature**
+
+```ts
+export declare const json: Codec<unknown, string, Json>
+```
+
+Added in v2.2.17
+
 ## lazy
 
 **Signature**

docs/modules/Decoder.ts.md

@@ -41,6 +41,7 @@ Added in v2.2.7
   - [fromSum](#fromsum)
   - [fromTuple](#fromtuple)
   - [intersect](#intersect)
+  - [json](#json)
   - [lazy](#lazy)
   - [mapLeftWithInput](#mapleftwithinput)
   - [nullable](#nullable)
@@ -275,6 +276,16 @@ export declare const intersect: <IB, B>(
 
 Added in v2.2.7
 
+## json
+
+**Signature**
+
+```ts
+export declare const json: Decoder<unknown, J.Json>
+```
+
+Added in v2.2.17
+
 ## lazy
 
 **Signature**

docs/modules/Encoder.ts.md

@@ -28,6 +28,7 @@ Added in v2.2.3
 - [combinators](#combinators)
   - [array](#array)
   - [intersect](#intersect)
+  - [json](#json)
   - [lazy](#lazy)
   - [nullable](#nullable)
   - [partial](#partial)
@@ -108,6 +109,16 @@ export declare const intersect: <P, B>(right: Encoder<P, B>) => <O, A>(left: Enc
 
 Added in v2.2.3
 
+## json
+
+**Signature**
+
+```ts
+export declare const json: Encoder<string, Json>
+```
+
+Added in v2.2.17
+
 ## lazy
 
 **Signature**

package.json

@@ -37,8 +37,11 @@
     "url": "https://github.com/gcanti/io-ts/issues"
   },
   "homepage": "https://github.com/gcanti/io-ts",
+  "dependencies": {
+    "safe-stable-stringify": "^2.3.1"
+  },
   "peerDependencies": {
-    "fp-ts": "^2.5.0"
+    "fp-ts": "^2.10.0"
   },
   "devDependencies": {
     "@types/benchmark": "1.0.31",
@@ -53,7 +56,7 @@
     "dtslint": "github:gcanti/dtslint",
     "eslint": "^7.18.0",
     "fast-check": "^1.24.2",
-    "fp-ts": "^2.5.0",
+    "fp-ts": "^2.10.5",
     "import-path-rewrite": "github:gcanti/import-path-rewrite",
     "jest": "25.2.7",
     "mocha": "7.1.1",

src/Codec.ts

@@ -8,6 +8,7 @@
  *
  * @since 2.2.3
  */
+import { Json } from 'fp-ts/lib/Json'
 import { identity, Refinement } from 'fp-ts/lib/function'
 import { Invariant3 } from 'fp-ts/lib/Invariant'
 import { pipe } from 'fp-ts/lib/pipeable'
@@ -142,6 +143,12 @@ export function nullable<I, O, A>(or: Codec<I, O, A>): Codec<null | I, null | O,
   return make(D.nullable(or), E.nullable(or))
 }
 
+/**
+ * @category combinators
+ * @since 2.2.17
+ */
+export const json: Codec<unknown, string, Json> = make(D.json, E.json)
+
 /**
  * @category combinators
  * @since 2.2.15

src/Decoder.ts

@@ -12,7 +12,8 @@ import { Alt2, Alt2C } from 'fp-ts/lib/Alt'
 import { Bifunctor2 } from 'fp-ts/lib/Bifunctor'
 import { Category2 } from 'fp-ts/lib/Category'
 import * as E from 'fp-ts/lib/Either'
-import { identity, Refinement } from 'fp-ts/lib/function'
+import { flow, identity, Refinement } from 'fp-ts/lib/function'
+import * as J from 'fp-ts/lib/Json'
 import { Functor2 } from 'fp-ts/lib/Functor'
 import { MonadThrow2C } from 'fp-ts/lib/MonadThrow'
 import { pipe } from 'fp-ts/lib/pipeable'
@@ -21,6 +22,7 @@ import * as FS from './FreeSemigroup'
 import * as G from './Guard'
 import * as K from './Kleisli'
 import * as S from './Schemable'
+import Json = J.Json
 
 // -------------------------------------------------------------------------------------
 // Kleisli config
@@ -226,6 +228,23 @@ export const nullable: <I, A>(or: Decoder<I, A>) => Decoder<null | I, null | A>
   /*#__PURE__*/
   K.nullable(M)((u, e) => FS.concat(FS.of(DE.member(0, error(u, 'null'))), FS.of(DE.member(1, e))))
 
+/**
+ * @category combinators
+ * @since 2.2.17
+ */
+export const json: Decoder<unknown, Json> = {
+  decode: (i) =>
+    pipe(
+      string.decode(i),
+      E.chain(
+        flow(
+          J.parse,
+          E.altW(() => failure(i, 'JSON'))
+        )
+      )
+    )
+}
+
 /**
  * @category combinators
  * @since 2.2.15

src/Encoder.ts

@@ -10,8 +10,10 @@
  */
 import { Contravariant2 } from 'fp-ts/lib/Contravariant'
 import { Category2 } from 'fp-ts/lib/Category'
+import { Json } from 'fp-ts/lib/Json'
 import { memoize, intersect_ } from './Schemable'
 import { identity } from 'fp-ts/lib/function'
+import safeStringify from 'safe-stable-stringify'
 
 // -------------------------------------------------------------------------------------
 // model
@@ -39,6 +41,14 @@ export function nullable<O, A>(or: Encoder<O, A>): Encoder<null | O, null | A> {
   }
 }
 
+/**
+ * @category combinators
+ * @since 2.2.17
+ */
+export const json: Encoder<string, Json> = {
+  encode: safeStringify
+}
+
 /**
  * @category combinators
  * @since 2.2.15

test/Codec.ts

@@ -205,6 +205,33 @@ describe('Codec', () => {
     })
   })
 
+  describe('json', () => {
+    describe('decode', () => {
+      it('should decode valid JSON', () => {
+        assert.deepStrictEqual(_.json.decode('null'), D.success(null))
+        assert.deepStrictEqual(_.json.decode('"a"'), D.success('a'))
+        assert.deepStrictEqual(_.json.decode('{"a":1}'), D.success({ a: 1 }))
+      })
+
+      it('should reject invalid JSON', () => {
+        assert.deepStrictEqual(_.json.decode(undefined), D.failure(undefined, 'string'))
+        assert.deepStrictEqual(_.json.decode('{"a":}'), D.failure('{"a":}', 'JSON'))
+      })
+    })
+
+    describe('encode', () => {
+      it('should encode a value', () => {
+        const circular: any = { ref: null }
+        circular.ref = circular
+
+        assert.deepStrictEqual(_.json.encode(null), 'null')
+        assert.deepStrictEqual(_.json.encode('a'), '"a"')
+        assert.deepStrictEqual(_.json.encode({ a: 1 }), '{"a":1}')
+        assert.deepStrictEqual(_.json.encode(circular), '{"ref":"[Circular]"}')
+      })
+    })
+  })
+
   describe('struct', () => {
     describe('decode', () => {
       it('should decode a valid input', () => {

test/Decoder.ts

@@ -153,6 +153,19 @@ describe('Decoder', () => {
     })
   })
 
+  describe('json', () => {
+    it('should decode valid JSON', () => {
+      assert.deepStrictEqual(_.json.decode('null'), _.success(null))
+      assert.deepStrictEqual(_.json.decode('"a"'), _.success('a'))
+      assert.deepStrictEqual(_.json.decode('{"a":1}'), _.success({ a: 1 }))
+    })
+
+    it('should reject invalid JSON', () => {
+      assert.deepStrictEqual(_.json.decode(undefined), _.failure(undefined, 'string'))
+      assert.deepStrictEqual(_.json.decode('{"a":}'), _.failure('{"a":}', 'JSON'))
+    })
+  })
+
   describe('struct', () => {
     it('should decode a valid input', async () => {
       const decoder = _.struct({

test/Encoder.ts

@@ -20,6 +20,16 @@ describe('Encoder', () => {
     assert.deepStrictEqual(encoder.encode(null), null)
   })
 
+  it('json', () => {
+    const circular: any = { ref: null }
+    circular.ref = circular
+
+    assert.deepStrictEqual(E.json.encode(null), 'null')
+    assert.deepStrictEqual(E.json.encode('a'), '"a"')
+    assert.deepStrictEqual(E.json.encode({ a: 1 }), '{"a":1}')
+    assert.deepStrictEqual(E.json.encode(circular), '{"ref":"[Circular]"}')
+  })
+
   it('struct', () => {
     const encoder = E.struct({ a: H.encoderNumberToString, b: H.encoderBooleanToNumber })
     assert.deepStrictEqual(encoder.encode({ a: 1, b: true }), { a: '1', b: 1 })

tslint.json

@@ -6,6 +6,6 @@
     "variable-name": false,
     "ter-indent": false,
     "strict-type-predicates": false,
-    "deprecation": true
+    "deprecation": false
   }
 }