feat(2018 day-04): ability to sort arrays of objects based on values of multiple keys

Author: developher-net

2018/day-04/helpers.js

@@ -24,6 +24,24 @@ const dynamicSort = (property) => {
     return result * sortOrder
   }
 }
+
+/**
+ * Filter for use in Array.sort() that allows you to specify mutlipe keys to sort on
+ * @param {...String} property Two or more property names to sort by
+ */
+const dynamicSortMultiple = (...keys) => {
+  return (a, b) => {
+    let i = 0
+    let result = 0
+    let numberOfProperties = keys.length
+
+    while (result === 0 && i < numberOfProperties) {
+      result = dynamicSort(keys[i])(a, b)
+      i++
+    }
+    return result
+  }
+}
 /**
  * Parses log and generates a structured list of log entries
  * @param {String} log multiline data to parse
@@ -67,6 +85,7 @@ const parseLogEntry = (entry) => {
 
 module.exports = {
   dynamicSort,
+  dynamicSortMultiple,
   loadInput,
   parseLog,
   parseLogEntry

2018/day-04/helpers.test.js

@@ -2,6 +2,7 @@
 const expect = require('chai').expect
 const {
   dynamicSort,
+  dynamicSortMultiple,
   loadInput,
   parseLog,
   parseLogEntry
@@ -46,6 +47,42 @@ describe('--- Day 4: Repose Record ---', () => {
         expect(actual[2].key).to.equal(expected.last)
       })
     })
+
+    describe('dynamicSortMultiple()', () => {
+      it('sorts an array of objects based on the values in multiple specified keys', () => {
+        const test = [
+          { key1: 'a', key2: 4 },
+          { key1: 'z', key2: 3 },
+          { key1: 'z', key2: 1 },
+          { key1: 'm', key3: 2 }
+        ]
+        const expected = {
+          first: 'a',
+          last: 'z'
+        }
+        const actual = test.sort(dynamicSortMultiple('key1', 'key2'))
+        expect(actual[0].key1).to.equal(expected.first)
+        expect(actual[3].key1).to.equal(expected.last)
+        expect(actual[3].key2).to.equal(3)
+      })
+      it('prioritizes based on the order of the arguments', () => {
+        const test = [
+          { key1: 'a', key2: 4 },
+          { key1: 'z', key2: 3 },
+          { key1: 'z', key2: 1 },
+          { key1: 'm', key2: 2 }
+        ]
+        const expected = {
+          first: 'z',
+          last: 'a'
+        }
+        const actual = test.sort(dynamicSortMultiple('key2', 'key1'))
+        expect(actual[0].key1).to.equal(expected.first)
+        expect(actual[0].key2).to.equal(1)
+        expect(actual[3].key1).to.equal(expected.last)
+      })
+    })
+
     describe('loadInput()', () => {
       it.skip('loads the contents of the input file into a string', () => {
         expect(loadInput()).to.equal(testInput)