Implement first simple version of sortMoveOperations

src/logic/sort.js

@@ -56,3 +56,37 @@ export function sortObjectKeys (object, direction = 1) {
 
   return sortedObject
 }
+
+/**
+ * Create an array containing all move operations
+ * needed to sort the array contents.
+ * @param {Array} array 
+ * @param {function (a, b) => number} comparator 
+ * @param {Array.<{fromIndex: number, toIndex: number}>} 
+ */
+export function sortMoveOperations (array, comparator) {
+  const operations = []
+
+  const sorted = array.slice()
+
+  for (let i = 1; i < sorted.length; i++) {
+    // TODO: implement a faster way to sort (binary tree sort?) 
+    // TODO: can we simplify the following code?
+    if (comparator(sorted[i - 1], sorted[i]) > 0) {
+      let j = i - 1
+      while (comparator(sorted[j - 1], sorted[i]) > 0 && j > 0) {
+        j--
+      }
+
+      operations.push({
+        fromIndex: i,
+        toIndex: j
+      })
+
+      const item = sorted.splice(i, 1)
+      sorted.splice(j, 0, [item])
+    }
+  }
+
+  return operations
+}

src/logic/sort.test.js

@@ -1,7 +1,7 @@
 import assert from 'assert'
-import { sortArray, sortObjectKeys } from './sort.js'
+import { sortArray, sortObjectKeys, sortMoveOperations } from './sort.js'
 
-describe('sort', () => {
+describe.only('sort', () => {
 
   it('should sort array', () => {
     assert.deepStrictEqual(sortArray([ 2, 3, 1 ]), [1, 2, 3])
@@ -31,4 +31,31 @@ describe('sort', () => {
     assert.deepStrictEqual(Object.keys(sortObjectKeys(object, -1)), ['c', 'b', 'a'])
   })
 
+  it('should give the move operations needed to sort given array', () => {
+    const comparator = (a, b) => a - b
+
+    assert.deepStrictEqual(sortMoveOperations([ 1, 2, 3 ], comparator), [])
+
+    assert.deepStrictEqual(sortMoveOperations([ 2, 3, 1 ], comparator), [
+      { fromIndex: 2, toIndex: 0 }
+    ])
+
+    assert.deepStrictEqual(sortMoveOperations([ 2, 1, 3 ], comparator), [
+      { fromIndex: 1, toIndex: 0 }
+    ])
+
+    assert.deepStrictEqual(sortMoveOperations([ 1, 3, 2 ], comparator), [
+      { fromIndex: 2, toIndex: 1 }
+    ])
+
+    assert.deepStrictEqual(sortMoveOperations([ 3, 2, 1 ], comparator), [
+      { fromIndex: 1, toIndex: 0 },
+      { fromIndex: 2, toIndex: 0 }
+    ])
+
+    assert.deepStrictEqual(sortMoveOperations([ 3, 1, 2 ], comparator), [
+      { fromIndex: 1, toIndex: 0 },
+      { fromIndex: 2, toIndex: 1 }
+    ])
+  })
 })