From 23495e0302b39fe464d4bdd7de9794ef553d9ce0 Mon Sep 17 00:00:00 2001
From: Vladimir Gorej <vladimir.gorej@gmail.com>
Date: Tue, 31 Jan 2017 20:32:07 +0100
Subject: [PATCH 1/3] feat(lens): add utils for further lens utilization

- added lensEq
- added lensSatisfies
---
 src/lens.js  | 15 ++++++++++++++-
 test/test.js | 25 ++++++++++++++++++++++---
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/src/lens.js b/src/lens.js
index f875f11..4a771cd 100644
--- a/src/lens.js
+++ b/src/lens.js
@@ -1,10 +1,23 @@
 var set = require('ramda/src/set')
 var lens = require('ramda/src/lens')
+var curry = require('ramda/src/curry')
+var view = require('ramda/src/view')
+var pipe = require('ramda/src/pipe')
+var equals = require('ramda/src/equals')
 
+var lensEq = curry(function(_lens, val, obj) {
+  return pipe(view(_lens), equals(val))(obj)
+});
+
+var lensSatisfies = curry(function(pred, _lens, obj) {
+  return pipe(view(_lens), pred, equals(true))(obj)
+});
 
 module.exports = {
   lens: lens,
   set: set,
   view: require('./view'),
-  over: require('./over')
+  over: require('./over'),
+  lensEq: lensEq,
+  lensSatisfies: lensSatisfies
 }
diff --git a/test/test.js b/test/test.js
index cbb5a96..81a0dce 100644
--- a/test/test.js
+++ b/test/test.js
@@ -1,12 +1,15 @@
-const assert = require("assert")
+const assert = require('assert')
 const L = require('../index')
-const R = require("ramda")
+const R = require('ramda')
 const compose = R.compose
 const lensProp = R.lensProp
 const lensIndex = R.lensIndex
+const equals = R.equals
 const set = L.set
 const view = L.view
 const over = L.over
+const lensEq = L.lensEq
+const lensSatisfies = L.lensSatisfies
 const mapped = L.mapped
 const traversed = L.traversed
 const traverseOf = L.traverseOf
@@ -35,7 +38,7 @@ describe("Lenses", function() {
   const zip = lensProp('zip')
 
 
-  describe("Set/View/Over", function() {
+  describe("Set/View/Over/LensEq/LensSatisfies", function() {
     const firstStreet = compose(_0, addresses, _0, street)
 
     it('gets the value', function() {
@@ -56,6 +59,22 @@ describe("Lenses", function() {
       assert.equal('393 Post Ave.', res[1].addresses[0].street)
       assert.equal('92 Oak St.', users[0].addresses[0].street)
     })
+
+    it('test if object has a specific value on provided lens', function() {
+      const res = lensEq(firstStreet, '92 Oak St.', users)
+      assert.ok(res)
+
+      const resCurried = lensEq(firstStreet)('92 Oak St.')(users)
+      assert.ok(resCurried)
+    })
+
+    it('test if specified object property at lens satisfies the given predicate', function() {
+      const res = lensSatisfies(equals('92 Oak St.'), firstStreet, users)
+      assert.ok(res)
+
+      const resCurried = lensSatisfies(equals('92 Oak St.'))(firstStreet)(users)
+      assert.ok(resCurried)
+    })
   })
 
   describe("Mapping", function() {

From 4e764201f84198878b7454778d19b2b52c6974c8 Mon Sep 17 00:00:00 2001
From: Vladimir Gorej <vladimir.gorej@gmail.com>
Date: Tue, 31 Jan 2017 20:51:21 +0100
Subject: [PATCH 2/3] feat(lens): add viewOr lens util

---
 src/lens.js  |  6 ++++++
 test/test.js | 12 ++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/src/lens.js b/src/lens.js
index 4a771cd..cc40807 100644
--- a/src/lens.js
+++ b/src/lens.js
@@ -4,6 +4,7 @@ var curry = require('ramda/src/curry')
 var view = require('ramda/src/view')
 var pipe = require('ramda/src/pipe')
 var equals = require('ramda/src/equals')
+var defaultTo = require('ramda/src/defaultTo')
 
 var lensEq = curry(function(_lens, val, obj) {
   return pipe(view(_lens), equals(val))(obj)
@@ -13,10 +14,15 @@ var lensSatisfies = curry(function(pred, _lens, obj) {
   return pipe(view(_lens), pred, equals(true))(obj)
 });
 
+var viewOr = curry(function (defaultValue, _lens, obj) {
+  return pipe(view(_lens), defaultTo(defaultValue))(obj)
+});
+
 module.exports = {
   lens: lens,
   set: set,
   view: require('./view'),
+  viewOr: viewOr,
   over: require('./over'),
   lensEq: lensEq,
   lensSatisfies: lensSatisfies
diff --git a/test/test.js b/test/test.js
index 81a0dce..fec128b 100644
--- a/test/test.js
+++ b/test/test.js
@@ -7,6 +7,7 @@ const lensIndex = R.lensIndex
 const equals = R.equals
 const set = L.set
 const view = L.view
+const viewOr = L.viewOr
 const over = L.over
 const lensEq = L.lensEq
 const lensSatisfies = L.lensSatisfies
@@ -75,6 +76,17 @@ describe("Lenses", function() {
       const resCurried = lensSatisfies(equals('92 Oak St.'))(firstStreet)(users)
       assert.ok(resCurried)
     })
+
+    it('test "view" of the given data structure, determined by the given lens with default value', function() {
+      const res = viewOr('default street', firstStreet, users)
+      assert.equal('92 Oak St.', res)
+
+      const resDefault = viewOr('default street', lensProp('non-existing-prop'), users)
+      assert.equal('default street', resDefault)
+
+      const resCurried = viewOr('default street')(firstStreet)(users)
+      assert.equal('92 Oak St.', resCurried)
+    })
   })
 
   describe("Mapping", function() {

From 7f57a055fe959fcce32e0d819c82327360cb9f06 Mon Sep 17 00:00:00 2001
From: Vladimir Gorej <vladimir.gorej@gmail.com>
Date: Tue, 31 Jan 2017 20:53:01 +0100
Subject: [PATCH 3/3] test(lens): add viewOr into test case description

---
 test/test.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test.js b/test/test.js
index fec128b..446422f 100644
--- a/test/test.js
+++ b/test/test.js
@@ -39,7 +39,7 @@ describe("Lenses", function() {
   const zip = lensProp('zip')
 
 
-  describe("Set/View/Over/LensEq/LensSatisfies", function() {
+  describe("Set/View/ViewOr/Over/LensEq/LensSatisfies", function() {
     const firstStreet = compose(_0, addresses, _0, street)
 
     it('gets the value', function() {