feat: add support for descending sort

all tests now working

fixes issue #6

Author: bjvickers

index.js

@@ -1,4 +1,3 @@
-const arrayify = require('array-back')
 const t = require('typical')
 
 /**
@@ -91,27 +90,31 @@ module.exports = sortBy
  * ```
  */
 function sortBy (recordset, sortBy, computedProperties) {
-  if (computedProperties) {
-    return recordset.sort(sortWithComputedProperties(sortBy))
-  } else {
-    return recordset.sort(sortWithoutComputedProperties(sortBy))
-  }
+  return recordset.sort(compare(sortBy, computedProperties))
 }
 
-// @TODO: Question - do we support crap data in? E.g. testing for 'isArrayLike',
+// @TODO: Question - do we support crap data in? E.g. testing for 't.isArrayLike',
 // @TODO: rather than just assuming the data in is correct?
-function sortWithoutComputedProperties (sortBy) {
-  let sorts = Object.entries(sortBy) // equiv: let sorts = sortBy.slice(0)
+function compare (sortBy, computedProperties) {
+  let sorts = Object.entries(sortBy)
   let propSort = sorts.shift()
   let property = t.isArrayLike(propSort) && propSort[0] || undefined
   let sort = t.isArrayLike(propSort) && propSort[1] || 'asc'
 
   return function sorter (a, b) {
+    let x
+    let y
     let result
-    const x = a[property]
-    const y = b[property]
-    let currentSort = sort
     let recurse
+    let currentSort = sort
+    
+    if (t.isDefined(computedProperties) && computedProperties.hasOwnProperty(property)) {
+      x = computedProperties[property](a)
+      y = computedProperties[property](b)
+    } else {
+      x = a[property]
+      y = b[property]
+    }
 
     if (t.isArrayLike(sort)) {
       // Custom sort the current property.
@@ -157,86 +160,3 @@ function sortWithoutComputedProperties (sortBy) {
     }
   }
 }
-
-/*
-function sortByCustom (properties, customOrder) {
-  let props = properties.slice(0)
-  let property = props.shift()
-  return function sorter (a, b) {
-    const x = a[property]
-    const y = b[property]
-    
-    let result = customOrder[property].indexOf(x) - customOrder[property].indexOf(y)
-
-    if (result === 0) {
-      if (props.length) {
-        property = props.shift()
-        return sorter(a, b)
-      } else {
-        props = properties.slice(0)
-        property = props.shift()
-        return 0
-      }
-    } else {
-      props = properties.slice(0)
-      property = props.shift()
-      return result
-    }
-  }
-}
-
-function sortByConvention (sortBy, customOrder) {
-  let sorts = sortBy.slice(0)
-  let propSort = sorts.shift()
-  let property = t.isArrayLike(propSort) && propSort[0] || undefined
-  let sort = t.isArrayLike(propSort) && propSort[1] || customOrder ? 'custom' : 'asc'
-  
-  return function sorter (a, b) {
-    let result
-    const x = a[property]
-    const y = b[property]
-    let currentSort = sort
-    let recurse
-
-    if (customOrder) {
-      result = customOrder[property].indexOf(x) - customOrder[property].indexOf(y)
-    } else {
-      // Perform the initial asc sort
-      if (x === null && y === null) {
-        result = 0
-      } else if ((!t.isDefined(x) || x === null) && t.isDefined(y)) {
-        result = -1
-      } else if (t.isDefined(x) && (!t.isDefined(y) || y === null)) {
-        result = 1
-      } else if (!t.isDefined(x) && !t.isDefined(y)) {
-        result = 0
-      } else {
-        result = x < y ? -1 : x > y ? 1 : 0
-      }
-    }
-    
-    // Reset this sorting function and parent, unless we have an equal
-    // result and there are more sorts still to perform, in which case
-    // move on to the next one.
-    if (result === 0 && sorts.length) {
-      recurse = true
-    } else {
-      recurse = false
-      sorts = sortBy.slice(0)
-    }
-    
-    propSort = sorts.shift()
-    property = t.isArrayLike(propSort) && propSort[0] || undefined
-    sort = t.isArrayLike(propSort) && propSort[1] || 'asc'
-
-    // Present the result
-    if (recurse) {
-      return sorter(a, b)
-    } else if ((result === 0) || (currentSort === 'asc')) {
-      return result
-    }  else {
-      return result * -1
-    }
-  }
-}
-*/

package-lock.json

@@ -20,10 +20,10 @@
   },
   "scripts": {
     "test": "test-runner test/*.js",
+    "test:computed": "node test/computed-property.js",
     "docs": "jsdoc2md -t README.hbs index.js > README.md; echo"
   },
   "dependencies": {
-    "array-back": "^3.0.0",
     "typical": "^3.0.0"
   },
   "devDependencies": {

package.json

@@ -27,7 +27,7 @@ runner.skip('computed property: anonymous', function () {
   a.deepStrictEqual(result, expected)
 })
 
-runner.skip('computed property: named', function () {
+runner.test('computed property: named', function () {
   const fixture = [
     { inner: { a: 5, b: 10 } },
     { inner: { a: 2, b: 10 } },
@@ -75,7 +75,7 @@ runner.skip('computed property: anonymous, descending order', function () {
   a.deepStrictEqual(result, expected)
 })
 
-runner.skip('computed property: named, descending custom order', function () {
+runner.test('computed property: named, descending custom order', function () {
   const fixture = [
     { inner: { number: 5 } },
     { inner: { number: 2 } },
@@ -84,11 +84,11 @@ runner.skip('computed property: named, descending custom order', function () {
     { inner: { number: 4 } }
   ]
   const expected = [
-    { inner: { number: 1 } },
-    { inner: { number: 2 } },
-    { inner: { number: 3 } },
+    { inner: { number: 5 } },
     { inner: { number: 4 } },
-    { inner: { number: 5 } }
+    { inner: { number: 3 } },
+    { inner: { number: 2 } },
+    { inner: { number: 1 } }
   ]
   const sortBy = {
     total: 'desc'
@@ -100,7 +100,7 @@ runner.skip('computed property: named, descending custom order', function () {
   a.deepStrictEqual(result, expected)
 })
 
-runner.skip('computed property: custom order', function () {
+runner.test('computed property: custom order', function () {
   const fixture = [
     { inner: { number: 5 } },
     { inner: { number: 2 } },
@@ -127,7 +127,7 @@ runner.skip('computed property: custom order', function () {
   a.deepStrictEqual(result, expected)
 })
 
-runner.skip('computed property: custom order, nulls', function () {
+runner.test('computed property: custom order, nulls', function () {
   const fixture = [
     { inner: { number: 5 } },
     { inner: { number: 2 } },

test/computed-property.js

@@ -387,7 +387,7 @@ runner.test('sort order: desc|asc|desc', function () {
   a.deepStrictEqual(result, expected)
 })
 
-runner.skip('sort order: computed property', function () {
+runner.test('sort order: computed property', function () {
   const fixture = [
     { inner: { number: 2 } },
     { inner: { number: 3 } },