feat: Add MongoDB ObjectId generation

src/database.ts

@@ -59,4 +59,53 @@ export class Database {
       this.faker.definitions.database.engine
     );
   }
+
+  /**
+   * Returns an [ObjectId](https://docs.mongodb.com/manual/reference/method/ObjectId/) string
+   *
+   * @param value When provided, and is a valid objectId, this method simply returns it as is.
+   *
+   * @example
+   * faker.database.objectId() // e175cac316a79afdd0ad3afb
+   * faker.database.objectId('6228fb6ec55ed495fc1e5f80') // 6228fb6ec55ed495fc1e5f80
+   */
+  objectId(value?: string): string {
+    const length = 24;
+
+    if (typeof value === 'string' && value?.length === 24) {
+      return value;
+    }
+
+    // a-z0-9
+    const charCodeOptions = [
+      {
+        min: 'a'.charCodeAt(0),
+        max: 'f'.charCodeAt(0),
+      },
+      {
+        min: '0'.charCodeAt(0),
+        max: '9'.charCodeAt(0),
+      },
+    ];
+
+    let returnString = '';
+
+    for (let i = 0; i < length; i++) {
+      // randomly chose if a number or letter should be selected
+      const charCodeOption =
+        charCodeOptions[
+          this.faker.datatype.number({
+            min: 0,
+            max: charCodeOptions.length - 1,
+          })
+        ];
+
+      // converts the randomly selected UTF-16 number to the corresponding character
+      returnString += String.fromCharCode(
+        this.faker.datatype.number(charCodeOption)
+      );
+    }
+
+    return returnString;
+  }
 }

test/database.spec.ts

@@ -9,6 +9,7 @@ const seededRuns = [
       type: 'smallint',
       collation: 'utf8_bin',
       engine: 'MEMORY',
+      objectId: 'e175cac316a79afdd0ad3afb',
     },
   },
   {
@@ -18,6 +19,7 @@ const seededRuns = [
       type: 'time',
       collation: 'utf8_general_ci',
       engine: 'MyISAM',
+      objectId: 'dbdab5c23ea3e1f70cc53cf4',
     },
   },
   {
@@ -27,13 +29,14 @@ const seededRuns = [
       type: 'geometry',
       collation: 'cp1250_general_ci',
       engine: 'ARCHIVE',
+      objectId: '47a0124a70679b99c9ad40b0',
     },
   },
 ];
 
 const NON_SEEDED_BASED_RUN = 5;
 
-const functionNames = ['column', 'type', 'collation', 'engine'];
+const functionNames = ['column', 'type', 'collation', 'engine', 'objectId'];
 
 describe('database', () => {
   afterEach(() => {
@@ -95,6 +98,20 @@ describe('database', () => {
           expect(faker.definitions.database.type).toContain(type);
         });
       });
+
+      describe('objectId', () => {
+        it('should generate a objectId value', () => {
+          const generateObjectId = faker.database.objectId();
+          expect(generateObjectId).toBeTypeOf('string');
+        });
+
+        it('should return the same value if valid value is passed', () => {
+          const generateObjectId = faker.database.objectId(
+            '6228fb6ec55ed495fc1e5f80'
+          );
+          expect(generateObjectId).toBe('6228fb6ec55ed495fc1e5f80');
+        });
+      });
     }
   });
 });