Modularise nth, pluck, range and reverse functions

index.js

@@ -13,6 +13,10 @@ const includes = require('./includes')
 const init = require('./init')
 const last = require('./last')
 const length = require('./length')
+const nth = require('./nth')
+const pluck = require('./pluck')
+const range = require('./range')
+const reverse = require('./reverse')
 
 const f2 = curry((name, arg, coll) => {
   return coll[name](arg)
@@ -31,10 +35,10 @@ ex.includes = includes
 ex.init = init
 ex.last = last
 ex.length = length
-ex.nth = curry((i, list) => list[i])
-ex.pluck = curry((key, list) => list.map(o => o[key]))
-ex.range = curry((start, end) => Array(end - start).fill(1).map((e, i) => i + start))
-ex.reverse = list => [].concat(list).reverse()
+ex.nth = nth
+ex.pluck = pluck
+ex.range = range
+ex.reverse = reverse
 ex.sort = list => [].concat(list).sort()
 ex.sortBy = curry((f, list) => [].concat(list).sort(f))
 ex.sum = list => list.reduce((sum, e) => sum + e, 0)

nth.js

@@ -0,0 +1,3 @@
+const curry = require('./curry')
+
+module.exports = curry((i, xs) => xs[i])

pluck.js

@@ -0,0 +1,3 @@
+const curry = require('./curry')
+
+module.exports = curry((key, xs) => xs.map(o => o[key]).filter(x => x != null))

range.js

@@ -0,0 +1,3 @@
+const curry = require('./curry')
+
+module.exports = curry((start, end) => Array(end - start).fill(1).map((e, i) => i + start))

reverse.js

@@ -0,0 +1 @@
+module.exports = xs => [].concat(xs).reverse()

test/append.js

@@ -1,5 +1,6 @@
 const assert = require('assert')
 const append = require('../append.js')
+const bf = require('../index.js')
 
 describe('append', () => {
 
@@ -17,4 +18,8 @@ describe('append', () => {
     assert.deepEqual(append(5, [1, 2, 3, 4]), [1, 2, 3, 4 ,5])
   })
 
+  it('is exported from index', () => {
+    assert.deepEqual(bf.append(5, [1, 2, 3, 4]), [1, 2, 3, 4 ,5])
+  })
+
 })

test/nth.js

@@ -0,0 +1,15 @@
+const assert = require('assert')
+const nth = require('../nth.js')
+const bf = require('../index.js')
+
+describe('nth', () => {
+
+  it('is curried', () => {
+    assert.strictEqual(nth(2)([1, 2, 3, 4]), 3);
+  })
+
+  it('should retrieve third item in a list', () => {
+    assert.strictEqual(nth(2, [1, 2, 3, 4, 5]), 3)
+  })
+
+})

test/pluck.js

@@ -1,11 +1,21 @@
 const assert = require('assert')
+const pluck = require('../pluck.js')
 const bf = require('../index.js')
 
 describe('pluck', () => {
 
+    it('is curried', () => {
+        assert.deepEqual(pluck('a')([{a: 1}, {a: 2}, {a: 3}]), [1, 2, 3])
+    })
+
     it('should pluck values from list of objects', () => {
-        const list = [{a: 1}, {a: 2}, {a: 3}]
-        assert.deepEqual(bf.pluck('a', list), [1, 2, 3])
+        const list = [{a: 1}, {b: 2}, {a: 3}]
+        assert.deepEqual(pluck('a', list), [1, 3])
+    })
+
+    it('is exported from the index file', () => {
+        const list = [{a: 1}, {b: 2}, {a: 3}]
+        assert.deepEqual(bf.pluck('a', list), [1, 3])
     })
 
-})
+})

test/range.js

@@ -0,0 +1,19 @@
+const assert = require('assert')
+const range = require('../range.js')
+const bf = require('../index.js')
+
+describe('range', () => {
+
+    it('is curried', () => {
+        assert.deepEqual(range(1)(5), [1, 2, 3, 4])
+    })
+
+    it('should create a range from 1 to 5 exclusive', () => {
+        assert.deepEqual(range(1, 5), [1, 2, 3, 4])
+    })
+
+    it('is exported from index', () => {
+        assert.deepEqual(bf.range(1, 5), [1, 2, 3, 4])
+    })
+
+})

test/reverse.js

@@ -1,15 +1,21 @@
 const assert = require('assert')
+const reverse = require('../reverse.js')
 const bf = require('../index.js')
 
 describe('reverse', () => {
 
-    it('should reverse list', () => {
+    it('should not mutate the list', () => {
         const list = [1, 2, 3, 4, 5]
-        assert.deepEqual(bf.reverse(list), [5, 4, 3, 2, 1])
+        assert.notEqual(reverse(list), list)
     })
 
-    it('should not mutate argument', () => {
+    it('should reverse the list', () => {
         const list = [1, 2, 3, 4, 5]
-        assert.notEqual(bf.reverse(list), list)
+        assert.deepEqual(reverse(list), [5, 4, 3, 2, 1])
+    })
+
+    it('should be exported from index', () => {
+        const list = [1, 2, 3, 4, 5]
+        assert.deepEqual(bf.reverse(list), [5, 4, 3, 2, 1])
     })
 })