feat(cms): add string transformation functions (#232)

* Add non overlapping transformation cases

* Complete non overlapping text transform functions

* Add tests for overlapping text transform cases

OMG TEST DRIVEN DEVELOPMENT

* Complete delete overlapping cases

* Correct delete tests to have expected output

* Correct application function in the tests and comment out DeleteDeleteSame test

* Everything working except for insertdelete overlap delete before insert

* Add copier dependency

* Complete go text transformation implementation and tests

* Add claification comments for tests

* Do not use copier library and remove from dependencies

* Complete go text transformation functions for same location insert

* Correct style and formatting of ts operation file

* Complete ts implementation with tests

* Remove console.logs

* Complete implementation of atomic operation in ts client

* Change interface variable names and add documentation on functions

* Also include the code for applying atomic operations

* Complete tests for path transform implementation

* merging with main

Co-authored-by: Varun Sethu <[email protected]>

Author: angary

backend/editor/OT/OTClient/client.ts

@@ -23,6 +23,14 @@ const ACK_TIMEOUT_DURATION = 10_000;
 */
 
 export default class Client {
+  private socket: Socket;
+
+  private queuedOperations: OperationQueue = new OperationQueue();
+  private pendingAcknowledgement = false;
+  private appliedOperations = 0;
+
+  private timeoutID: number = NaN;
+
   // TODO: Handle destruction / closing of the websocket
   constructor(opCallback: (op: Operation) => void) {
     this.socket = io(`ws://localhost:8080/edit?document=${document}`);
@@ -94,12 +102,4 @@ export default class Client {
       "finish"
     );
   };
-
-  private socket: Socket;
-
-  private queuedOperations: OperationQueue = new OperationQueue();
-  private pendingAcknowledgement = false;
-  private appliedOperations = 0;
-
-  private timeoutID: number = NaN;
 }

backend/editor/OT/OTClient/jest.config.js

@@ -0,0 +1,5 @@
+/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+};

backend/editor/OT/OTClient/operation.test.ts

@@ -0,0 +1,130 @@
+import { AtomicOperation, StringOperation } from "./operation";
+
+describe("String transformation functions", () => {
+
+  const s = "abcde";
+
+  const apply = (o: AtomicOperation, s: string): string => {
+    const strOp = o as StringOperation;
+    const start = Math.min(s.length, strOp.start);
+    const end = strOp.newValue == "" ? strOp.end : start;
+    return s.substring(0, start) + strOp.newValue + s.substring(end);
+  };
+
+  describe("insert insert", () => {
+    test("non overlap", () => {
+      const o1 = new StringOperation(1, 2, "1");
+      const o2 = new StringOperation(2, 3, "2");
+      expect(apply(o1, s)).toBe("a1bcde");
+      expect(apply(o2, s)).toBe("ab2cde");
+
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("a1b2cde");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("a1b2cde");
+    });
+
+    test("same location", () => {
+      const o1 = new StringOperation(1, 2, "2");
+      const o2 = new StringOperation(1, 2, "1");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("a12bcde");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("a12bcde");
+    });
+
+    test("overlap", () => {
+      const o1 = new StringOperation(1, 3, "11");
+      const o2 = new StringOperation(2, 4, "22");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("a11b22cde");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("a11b22cde");
+    });
+  });
+
+  describe("insert delete", () => {
+    test("non overlap", () => {
+      const o1 = new StringOperation(1, 2, "1");
+      const o2 = new StringOperation(2, 3, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("a1bde");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("a1bde");
+    });
+
+    test("same location", () => {
+      const o1 = new StringOperation(1, 2, "1");
+      const o2 = new StringOperation(0, 1, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("1bcde");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("1bcde");
+    });
+
+    test("overlap insert before delete", () => {
+      const o1 = new StringOperation(1, 3, "12");
+      const o2 = new StringOperation(0, 1, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("12bcde");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("12bcde");
+    });
+
+    test("overlap delete before insert", () => {
+      const o1 = new StringOperation(2, 3, "1");
+      const o2 = new StringOperation(0, 3, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("1de");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("1de");
+    });
+
+    test("overlap less insert than delete", () => {
+      const o1 = new StringOperation(0, 1, "1");
+      const o2 = new StringOperation(0, 5, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("1");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("1");
+    });
+
+    test("overlap more insert than delete", () => {
+      const o1 = new StringOperation(0, 5, "11111");
+      const o2 = new StringOperation(0, 1, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("11111bcde");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("11111bcde");
+    });
+  });
+
+  describe("delete delete", () => {
+    test("non overlap", () => {
+      const o1 = new StringOperation(1, 2, "");
+      const o2 = new StringOperation(2, 3, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("ade");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("ade");
+    });
+
+    test("same operations", () => {
+      const o1 = new StringOperation(1, 2, "");
+      const o2 = new StringOperation(1, 2, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("acde");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("acde");
+    });
+
+    test("overlap", () => {
+      const o1 = new StringOperation(1, 3, "");
+      const o2 = new StringOperation(2, 3, "");
+      const [o1_t1, o2_t1] = o1.transformAgainst(o2);
+      const [o1_t2, o2_t2] = o2.transformAgainst(o1);
+      expect(apply(o1_t1, apply(o2_t1, s))).toBe("ade");
+      expect(apply(o2_t2, apply(o1_t2, s))).toBe("ade");
+    });
+  });
+});