fix(lens): fix false values from short circuiting with nullish

fix #33

.babelrc

@@ -1,7 +1,10 @@
 {
   "env": {
     "test": {
-      "plugins": ["@babel/plugin-transform-modules-commonjs"]
+      "plugins": [
+        "@babel/plugin-proposal-nullish-coalescing-operator",
+        "@babel/plugin-transform-modules-commonjs"
+      ]
     }
   }
 }

.eslintrc.yml

@@ -8,6 +8,7 @@ parserOptions:
   ecmaVersion: 12
   sourceType: module
 rules:
+  no-unused-vars: warn
   simple-import-sort/sort: warn
 parser: '@babel/eslint-parser'
 plugins:

__tests__/operations.test.js

@@ -15,7 +15,6 @@ const theme = {
   },
 }
 const fontLense = path(['styles', 'CodeSurfer', 'code', 'fontFamily'])
-
 const themeWithoutFontFamily = {
   styles: {
     CodeSurfer: {
@@ -66,6 +65,15 @@ describe('Operations over Optics', () => {
     expect(view(fontLense, newTheme)).toBe('MONOSPACED')
   })
 
+  test('over should work with boolean functions', () => {
+    const neg = x => !x
+    const liked = { liked: true }
+    const lens = optic('liked')
+
+    expect(view(lens, liked)).toBe(true)
+    expect(view(lens, over(lens, neg, liked))).toBe(false)
+  })
+
   test('path should create the same lense as a manually defined one', () => {
     const hardLense = optic(
       alter('styles'),

package.json

@@ -36,6 +36,7 @@
     "@babel/core": "^7.11.6",
     "@babel/eslint-parser": "^7.11.5",
     "@babel/eslint-plugin": "^7.11.5",
+    "@babel/plugin-proposal-nullish-coalescing-operator": "^7.10.4",
     "@babel/plugin-transform-modules-commonjs": "^7.10.4",
     "@commitlint/cli": "latest",
     "@commitlint/config-conventional": "latest",
@@ -99,7 +100,7 @@
   "jest": {
     "coverageThreshold": {
       "global": {
-        "branches": 98,
+        "branches": 100,
         "functions": 95,
         "lines": 100,
         "statements": 97

src/Lens.js

@@ -68,7 +68,7 @@ export const mustBePresent = key => lens(get(key), set(key))
 // alter : String → Lens (Maybe s) (Maybe a)
 export const alter = key =>
   lens(
-    obj => (isNotFound(obj) ? notFound : obj[key] || notFound),
+    obj => (isNotFound(obj) ? notFound : obj[key] ?? notFound),
     (val, obj) => {
       if (isNotFound(val)) {
         if (typeof obj === 'object') {

src/Optional.js

@@ -56,14 +56,14 @@ export const optional = curry((preview, set) => new Optional(preview, set))
 // optionalProp : String → Optional s a
 export const optionalProp = key =>
   optional(
-    obj => obj[key] || notFound,
+    obj => obj[key] ?? notFound,
     (val, obj) => (obj[key] ? { ...obj, [key]: val } : obj),
   )
 
 // optionalIx : Number → Optional s a
 export const optionalIx = index =>
   optional(
-    obj => obj[index] || notFound,
+    obj => obj[index] ?? notFound,
     (val, obj) => (obj[index] ? setIndex(index, val, obj) : obj),
   )