feat(helpers): fake from array

Author: ST-DDT

src/modules/helpers/index.ts

@@ -690,4 +690,33 @@ export class HelpersModule {
       currentIterations: 0,
     });
   }
+
+  /**
+   * Generates an array containing values returned by the given method.
+   *
+   * @param method The method used to generate the values.
+   * @param options The optional options object.
+   * @param options.count The number of elements to generate. Defaults to `3`.
+   * @param options.unique Whether the generated elements should be unique per array. Defaults to `false`.
+   *
+   * @example
+   * faker.helpers.multiple(faker.person.firstName) // [ 'Aniya', 'Norval', 'Dallin' ]
+   * faker.helpers.multiple(faker.person.firstName, { count: 3 }) // [ 'Santos', 'Lavinia', 'Lavinia' ]
+   * faker.helpers.multiple(faker.person.firstName, { count: 3, unique: true }) // [ 'Santos', 'Nedra', 'Lavinia' ]
+   *
+   * @since 8.0.0
+   */
+  multiple<T>(
+    method: () => T,
+    options: { count?: number; unique?: boolean } = {}
+  ): T[] {
+    // TODO @ST-DDT 2022-11-09: Add support for count ranges
+    const { count = 3, unique = false } = options;
+
+    if (unique) {
+      // TODO @ST-DDT 2022-11-09: Fix unique method signature
+    }
+
+    return Array.from({ length: count }, method);
+  }
 }

test/__snapshots__/helpers.spec.ts.snap

@@ -37,6 +37,34 @@ exports[`helpers > 42 > maybe > with only value 1`] = `"Hello World!"`;
 
 exports[`helpers > 42 > maybe > with value and probability 1`] = `undefined`;
 
+exports[`helpers > 42 > multiple > with method and count 1`] = `
+[
+  37454,
+  79654,
+  95071,
+  18343,
+  73199,
+]
+`;
+
+exports[`helpers > 42 > multiple > with method, count and unique 1`] = `
+[
+  37454,
+  79654,
+  95071,
+  18343,
+  73199,
+]
+`;
+
+exports[`helpers > 42 > multiple > with only method 1`] = `
+[
+  37454,
+  79654,
+  95071,
+]
+`;
+
 exports[`helpers > 42 > mustache > template with method 1`] = `"Hello John!"`;
 
 exports[`helpers > 42 > mustache > template with string 1`] = `"Hello John!"`;
@@ -189,6 +217,34 @@ exports[`helpers > 1211 > maybe > with only value 1`] = `undefined`;
 
 exports[`helpers > 1211 > maybe > with value and probability 1`] = `undefined`;
 
+exports[`helpers > 1211 > multiple > with method and count 1`] = `
+[
+  92852,
+  45901,
+  89347,
+  77826,
+  22557,
+]
+`;
+
+exports[`helpers > 1211 > multiple > with method, count and unique 1`] = `
+[
+  92852,
+  45901,
+  89347,
+  77826,
+  22557,
+]
+`;
+
+exports[`helpers > 1211 > multiple > with only method 1`] = `
+[
+  92852,
+  45901,
+  89347,
+]
+`;
+
 exports[`helpers > 1211 > mustache > template with method 1`] = `"Hello John!"`;
 
 exports[`helpers > 1211 > mustache > template with string 1`] = `"Hello John!"`;
@@ -331,6 +387,34 @@ exports[`helpers > 1337 > maybe > with only value 1`] = `"Hello World!"`;
 
 exports[`helpers > 1337 > maybe > with value and probability 1`] = `undefined`;
 
+exports[`helpers > 1337 > multiple > with method and count 1`] = `
+[
+  26202,
+  56052,
+  15868,
+  21258,
+  27812,
+]
+`;
+
+exports[`helpers > 1337 > multiple > with method, count and unique 1`] = `
+[
+  26202,
+  56052,
+  15868,
+  21258,
+  27812,
+]
+`;
+
+exports[`helpers > 1337 > multiple > with only method 1`] = `
+[
+  26202,
+  56052,
+  15868,
+]
+`;
+
 exports[`helpers > 1337 > mustache > template with method 1`] = `"Hello John!"`;
 
 exports[`helpers > 1337 > mustache > template with string 1`] = `"Hello John!"`;

test/helpers.spec.ts

@@ -112,6 +112,15 @@ describe('helpers', () => {
         .it('with () => number', faker.datatype.number)
         .it('with () => number and args', faker.datatype.number, [50]);
     });
+
+    t.describe('multiple', (t) => {
+      t.it('with only method', faker.datatype.number)
+        .it('with method and count', faker.datatype.number, { count: 5 })
+        .it('with method, count and unique', faker.datatype.number, {
+          count: 5,
+          unique: true,
+        });
+    });
   });
 
   describe(`random seeded tests for seed ${faker.seed()}`, () => {
@@ -844,5 +853,37 @@ Try adjusting maxTime or maxRetries parameters for faker.helpers.unique().`)
         expect(store).toEqual({ 'with conflict: 0': 'with conflict: 0' });
       });
     });
+
+    describe('multiple()', () => {
+      it('should generate values from the function', () => {
+        const result = faker.helpers.multiple(faker.person.firstName);
+        expect(result).toBeTypeOf('object');
+        expect(Array.isArray(result)).toBe(true);
+        expect(result.length).toBe(3);
+      });
+
+      it('should generate the given amount of values from the function', () => {
+        const result = faker.helpers.multiple(faker.person.firstName, {
+          count: 5,
+        });
+        expect(result).toBeTypeOf('object');
+        expect(Array.isArray(result)).toBe(true);
+        expect(result.length).toBe(5);
+      });
+
+      it.todo(
+        'should generate the given amount of unique values from the function',
+        () => {
+          const result = faker.helpers.multiple(faker.person.firstName, {
+            count: 10,
+            unique: true,
+          });
+          expect(result).toBeTypeOf('object');
+          expect(Array.isArray(result)).toBe(true);
+          expect(result.length).toBe(10);
+          expect(result).not.toContainDuplicates();
+        }
+      );
+    });
   });
 });