Add option for enums and more instances (#9)

Instances for `Either`, `JSDate`.
And some bullshit coverage.

Author: i-am-the-slime

.github/workflows/ci.yml

@@ -34,4 +34,4 @@ jobs:
       - run: npm install
       - run: spago build
 
-      - run: spago -x test.dhall test
+      - run: npm run coverage

.gitignore

@@ -6,3 +6,5 @@
 /.purs*
 /.psa*
 /.spago/
+/.nyc_output/
+/coverage/

.nycrc.json

@@ -0,0 +1,8 @@
+{
+  "all": true,
+  "extension": [".purs"],
+  "include": [ "src/**/*.purs"],
+  "exclude": [ "src/Yoga/JSON/Generics.purs"],
+  "excludeAfterRemap": true,
+  "sourceMap": true
+}

README.md

@@ -20,24 +20,33 @@ Check out the tests for how to encode/decode increasingly complex types.
 
 ## Migrate from `purescript-simple-json`
 
-`purescript-yoga-json` is a drop-in replacement for `purescript-simple-json`. Just change the imports from `Simple.JSON` to `Yoga.JSON`.
+`purescript-yoga-json` is almost (read below if you use variants) a drop-in replacement for `purescript-simple-json`. Just change the imports from `Simple.JSON` to `Yoga.JSON`.
 
-## Differences to `simple-json`
+## Additions over `simple-json`
 
 ### Tuples
 There is an inbuilt codec for `Tuple`s thanks to @ursi
+`yoga-json` represents tuples as arrays in JSON.
+
+### Tuples
+There is an inbuilt codec for `Either`s.
+`yoga-json` represents eithers as objects with a `type` and a `value` tag in JSON.
 
 ### Generics
 It includes @justinwoo's codecs for en- and decoding generics inspired by
 [simple-json-generics](https://github.com/justinwoo/purescript-simple-json-generics)
 
+It is possible to customise the representation of enums, tagged sum types, and untagged sum types via options.
+
 ### BigInts
 It can *read* bigints (if you install `big-integer` as a JS dependency).
 
 ### 💣 Cannot write bigints as bigints but only strings
 It seems that there is no way to write bigints in JavaScript except for writing your own `JSON.stringify`.
 
-### 💣 The Variant Codec is different
+## Differences to `simple-json`
+
+### 💣 Variant codec
 If you want to emulate `simple-json`'s format you may use the newtype  `TaggedVariant`
 
 ```purescript