From a0406bd8497c83fb42d7a4b5e037e55beb055b12 Mon Sep 17 00:00:00 2001
From: James Smith <james@lumenlearning.com>
Date: Fri, 10 Apr 2020 13:17:14 -0600
Subject: [PATCH] add grading algorithm for cloze drag and drop

---
 src/grader.ts       | 24 ++++++++++++++++++++++++
 src/types.ts        |  1 +
 test/grader.spec.ts | 19 +++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/src/grader.ts b/src/grader.ts
index d5feece..7ffc280 100644
--- a/src/grader.ts
+++ b/src/grader.ts
@@ -16,6 +16,30 @@ const grader = (question: Question, choices: Array<Array<Choice>>, response: Res
             return (currentChosenChoice && currentChosenChoice.correct) ? 1.0 : 0.0;
         }).reduce((sum, resp) => (sum += resp), 0);
         return correctResponses / choices.length;
+    } else if (question.questionType === "CLOZE_DRAG_AND_DROP") {
+        let ccio = choices[0].sort((a, b) => a.correctOrder - b.correctOrder);
+        let ccioKeys = ccio.map((cc) => cc.key);
+        let exactSameOrderKeys = true;
+        for (let i = 0; i < ccioKeys.length; i++) {
+            if (ccioKeys[i] !== response.keys[i]) {
+                exactSameOrderKeys = false;
+            }
+        }
+        if (exactSameOrderKeys) {
+            return 1.0;
+        } else {
+            let allKeysPresent = true;
+            for (let k of response.keys) {
+                if (!ccioKeys.includes(k)) {
+                    allKeysPresent = false;
+                }
+            }
+            if (allKeysPresent) {
+                return 0.5;
+            } else {
+                return 0.0;
+            }
+        }
     } else {
         return 0.0;
     }
diff --git a/src/types.ts b/src/types.ts
index 9a6c44d..694606b 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -7,6 +7,7 @@ export interface Choice {
     readonly key: string,
     readonly text: string,
     readonly correct: boolean,
+    correctOrder?: number,
 }
 
 export interface Response {
diff --git a/test/grader.spec.ts b/test/grader.spec.ts
index 211ab66..1078207 100644
--- a/test/grader.spec.ts
+++ b/test/grader.spec.ts
@@ -73,4 +73,23 @@ describe("grader", () => {
             expect(grader(question, choices, { keys: [ "A", "C" ] })).toEqual(0.5)
         });
     });
+
+    describe("CLOZE_DRAG_AND_DROP", () => {
+        const question = {
+            questionType: "CLOZE_DRAG_AND_DROP",
+            prompt: "For {target1}, then {target2}",
+        };
+        const choices = [[
+            { key: "A", text: "A", correct: true, correctOrder: 1 },
+            { key: "B", text: "B", correct: true, correctOrder: 2 },
+        ]];
+
+        it("should return 1.0 if responses match correct choices in order", () => {
+            expect(grader(question, choices, { keys: ["A", "B"] })).toEqual(1.0);
+        });
+
+        it("should return 0.5 if responses are out of order", () => {
+            expect(grader(question, choices, { keys: ["B", "A"] })).toEqual(0.5);
+        });
+    });
 });