feature/create functionality

lib/json-file-crud.js

@@ -14,12 +14,49 @@ class JsonFileCRUD {
     }
     this.filePath = path.resolve(filePath);
     this.idField = options.idField || "id";
+    this.writeQueue = [];
+    this.isWriting = false;
   }
 
   //#region CREATE
 
-  create(data, callback) {
-    // TODO: implement create
+  create(item, callback) {
+    // Add to queue if already processing
+    if (this.isWriting) {
+      this.writeQueue.push({ 
+        type: 'create', 
+        item: item, 
+        callback: callback 
+      });
+      return;
+    }
+
+    this.isWriting = true;
+
+    this.readAll((err, items) => {
+      if (err) {
+        this.isWriting = false;
+        this.processWriteQueue();
+        return callback(err);
+      }
+
+      // Add new item to array
+      items.push(item);
+
+      // Write back to file
+      const content = JSON.stringify(items, null, 2);
+      fs.writeFile(this.filePath, content, (writeErr) => {
+        this.isWriting = false;
+
+        if (writeErr) {
+          callback(writeErr);
+        } else {
+          callback(null, item);
+        }
+
+        this.processWriteQueue();
+      });
+    });
   }
 
   //#endregion CREATE
@@ -110,6 +147,45 @@ class JsonFileCRUD {
   }
 
   //#endregion DELETE
+
+  /**
+   * Writes items array to file, replacing all content
+   * @param {Object[]} items - Array of items to save
+   * @param {Function} callback - Called with (error)
+   */
+  writeAll(items, callback) {
+    // Add to queue if already writing
+    if (this.isWriting) {
+      this.writeQueue.push({ items, callback });
+      return;
+    }
+
+    this.isWriting = true;
+
+    const content = JSON.stringify(items, null, 2);
+    fs.writeFile(this.filePath, content, (writeErr) => {
+      this.isWriting = false;
+      callback(writeErr);
+      this.processWriteQueue();
+    });
+  }
+
+  /**
+   * Process queued write operations
+   */
+  processWriteQueue() {
+    if (this.writeQueue.length > 0 && !this.isWriting) {
+      const queuedOperation = this.writeQueue.shift();
+
+      if (queuedOperation.type === 'create') {
+        // Handle create operation
+        this.create(queuedOperation.item, queuedOperation.callback);
+      } else {
+        // Handle writeAll operation
+        this.writeAll(queuedOperation.items, queuedOperation.callback);
+      }
+    }
+  }
 }
 
 export default JsonFileCRUD;

package.json

@@ -7,9 +7,10 @@
   "type": "module",
   "scripts": {
     "start": "node .",
-    "test": "node test/test-basic.js && node test/test-read.js",
+    "test": "node test/test-basic.js && node test/test-read.js && node test/test-create.js",
     "test:basic": "node test/test-basic.js",
     "test:read": "node test/test-read.js",
+    "test:create": "node test/test-create.js",
     "prepublishOnly": "npm test"
   },
   "keywords": [

test/test-create.js

@@ -0,0 +1,155 @@
+import JsonFileCRUD from "../lib/json-file-crud.js";
+import fs from "fs";
+
+// Test setup
+const testFile = "./test-create-data.json";
+const crud = new JsonFileCRUD(testFile);
+let passed = 0;
+let total = 0;
+let completed = 0;
+
+function test(description, testFn) {
+  total++;
+  testFn((err, success) => {
+    completed++;
+
+    if (err || !success) {
+      console.log(`✗ ${description}: ${err?.message || 'failed'}`);
+    } else {
+      console.log(`✓ ${description}`);
+      passed++;
+    }
+
+    // Check if all async tests are done
+    if (completed === total) {
+      console.log(`\n${passed}/${total} tests passed`);
+      // Clean up test file
+      if (fs.existsSync(testFile)) {
+        fs.unlinkSync(testFile);
+      }
+      process.exit(passed === total ? 0 : 1);
+    }
+  });
+}
+
+// Clean up and start fresh
+if (fs.existsSync(testFile)) {
+  fs.unlinkSync(testFile);
+}
+
+// Test create single item
+test('create single item works', (done) => {
+  crud.create({ id: 1, name: "Ariel" }, (err, item) => {
+    if (err) return done(err);
+    if (item.name === "Ariel") return done(null, true);
+    done(new Error('wrong item data'));
+  });
+});
+
+// Test create and verify item exists
+test('create and verify item exists', (done) => {
+  crud.create({ id: 2, name: "Yoni" }, (err, item) => {
+    if (err) return done(err);
+
+    // Verify it was saved
+    crud.findById(2, (err2, foundItem) => {
+      if (err2) return done(err2);
+      if (foundItem && foundItem.name === "Yoni") return done(null, true);
+      done(new Error('item not found after create'));
+    });
+  });
+});
+
+// Test create multiple items
+test('create multiple items works', (done) => {
+  crud.create({ id: 3, name: "Moshe" }, (err, item) => {
+    if (err) return done(err);
+
+    crud.create({ id: 4, name: "Nissim" }, (err2, item2) => {
+      if (err2) return done(err2);
+
+      // Verify both items exist
+      crud.count((err3, count) => {
+        if (err3) return done(err3);
+        // Should have 4 items total (from previous tests)
+        if (count === 4) return done(null, true);
+        done(new Error(`expected 4 items, got ${count}`));
+      });
+    });
+  });
+});
+
+// Test concurrent creates (queue test)
+test('concurrent creates work with queue', (done) => {
+  // Create a separate instance for this test
+  const testFile2 = "./test-concurrent-data.json";
+  const crud2 = new JsonFileCRUD(testFile2);
+
+  // Clean up test file
+  if (fs.existsSync(testFile2)) {
+    fs.unlinkSync(testFile2);
+  }
+
+  let completedCreates = 0;
+  const totalCreates = 3;
+
+  // Create multiple items at the same time
+  crud2.create({ id: 10, name: "Concurrent1" }, (err, item) => {
+    if (err) return done(err);
+    completedCreates++;
+    checkCompletion();
+  });
+
+  crud2.create({ id: 11, name: "Concurrent2" }, (err, item) => {
+    if (err) return done(err);
+    completedCreates++;
+    checkCompletion();
+  });
+
+  crud2.create({ id: 12, name: "Concurrent3" }, (err, item) => {
+    if (err) return done(err);
+    completedCreates++;
+    checkCompletion();
+  });
+
+  function checkCompletion() {
+    if (completedCreates === totalCreates) {
+      // All creates completed, now verify all items exist
+      crud2.count((err, count) => {
+        // Clean up test file
+        if (fs.existsSync(testFile2)) {
+          fs.unlinkSync(testFile2);
+        }
+
+        if (err) return done(err);
+        if (count === 3) return done(null, true);
+        done(new Error(`expected 3 items, got ${count}`));
+      });
+    }
+  }
+});
+
+// Test create with different data types
+test('create with different data types works', (done) => {
+  const complexItem = {
+    id: 5,
+    name: "Moshe",
+    age: 30,
+    active: true,
+    tags: ["test", "demo"],
+    profile: { city: "Jerusalem", country: "Israel" }
+  };
+
+  crud.create(complexItem, (err, item) => {
+    if (err) return done(err);
+
+    // Verify complex data was saved correctly
+    crud.findById(5, (err2, foundItem) => {
+      if (err2) return done(err2);
+      if (foundItem && foundItem.name === "Moshe" && foundItem.age === 30 && foundItem.active === true) {
+        return done(null, true);
+      }
+      done(new Error('complex item not saved correctly'));
+    });
+  });
+});