Support for [email protected] (#11)

* add support for [email protected]
* fix typo in installPeerDependencies npm script
* fix broken link to Either.ts in README.md

README.md

@@ -11,7 +11,7 @@ It provides the following:
 
 ### Promise chain decoding
 
-Decode data from Promise based APIs, without having to worry about how to retrieve data from the [Either](https://github.com/gcanti/fp-ts/blob/master/docs/Either.md) values returned by the `io-ts` types.
+Decode data from Promise based APIs, without having to worry about how to retrieve data from the [Either](https://gcanti.github.io/fp-ts/modules/Either.ts.html) values returned by the `io-ts` types.
 
 ```typescript
 import * as t from 'io-ts';

package.json

@@ -19,8 +19,8 @@
     "lint:typescript": "tsc --noEmit",
     "test:js": "mocha -r ts-node/register test/*.ts",
     "build": "tsc",
-    "installPeerDepenencies": "npm install --no-save io-ts@1.x",
-    "prepublish": "npm run installPeerDepenencies && npm run build"
+    "installPeerDependencies": "npm install --no-save io-ts@2.x fp-ts@2.x",
+    "prepublish": "npm run installPeerDependencies && npm run build"
   },
   "repository": {
     "type": "git",
@@ -36,7 +36,8 @@
     "deep-equal": "^1.0.1"
   },
   "peerDependencies": {
-    "io-ts": "1.x"
+    "fp-ts": "2.x",
+    "io-ts": "2.x"
   },
   "devDependencies": {
     "@types/chai": "^4.1.7",
@@ -45,7 +46,6 @@
     "@types/mocha": "^5.2.7",
     "chai": "^4.2.0",
     "chai-as-promised": "^7.1.1",
-    "fp-ts": "^1.19.0",
     "mocha": "^6.1.4",
     "prettier": "^1.18.2",
     "ts-node": "^8.3.0",

src/index.ts

@@ -1,4 +1,5 @@
 import deepEqual from 'deep-equal';
+import { either, fold } from 'fp-ts/lib/Either';
 import * as t from 'io-ts';
 import { PathReporter } from 'io-ts/lib/PathReporter';
 
@@ -36,12 +37,10 @@ export function decode<Output, Input>(
         Promise<Output>
       >(null, type);
     default:
-      return type
-        .decode(value || arguments[2])
-        .fold(
-          errors => Promise.reject(new DecodeError(errors)),
-          decodedValue => Promise.resolve(decodedValue),
-        );
+      return fold<t.Errors, Output, Promise<Output>>(
+        errors => Promise.reject(new DecodeError(errors)),
+        decodedValue => Promise.resolve(decodedValue),
+      )(type.decode(value || arguments[2]));
   }
 }
 
@@ -156,7 +155,7 @@ export function extendDecoder<Input, Output>(
     value: unknown,
     context: t.Context,
   ) => {
-    return baseDecoder.validate(value, context).chain(chainedValue => {
+    return either.chain(baseDecoder.validate(value, context), chainedValue => {
       try {
         return t.success(decode(chainedValue));
       } catch (e) {

test/helpers/chai-fp-ts.ts

@@ -22,16 +22,23 @@ interface Utils {
 export default function(chai: Chai, utils: Utils) {
   const Assertion = chai.Assertion;
 
+  function isObject(value: unknown): value is object {
+    return typeof value === 'object' && value !== null;
+  }
+
   function isEither<L, A>(value: unknown): value is Either.Either<L, A> {
-    return value instanceof Either.Left || value instanceof Either.Right;
+    if (!isObject(value)) {
+      return false;
+    }
+    return Either.isLeft(value as any) || Either.isRight(value as any);
   }
 
   Assertion.addProperty('left', function() {
     const obj = this._obj;
     let isLeft: boolean = false;
 
-    if (isEither(obj) && obj.isLeft()) {
-      utils.flag(this, 'object', obj.value);
+    if (isEither(obj) && Either.isLeft(obj)) {
+      utils.flag(this, 'object', obj.left);
       isLeft = true;
     }
 
@@ -46,8 +53,8 @@ export default function(chai: Chai, utils: Utils) {
     const obj = this._obj;
     let isRight: boolean = false;
 
-    if (isEither(obj) && obj.isRight()) {
-      utils.flag(this, 'object', obj.value);
+    if (isEither(obj) && Either.isRight(obj)) {
+      utils.flag(this, 'object', obj.right);
       isRight = true;
     }