feat: add mapParallel and mapSequential commands

src/core/commands/functional.spec.ts

@@ -0,0 +1,60 @@
+import { CommandQueue } from '../command-queue';
+import { mapParallel, mapSequential } from './functional';
+import { sequence, waitForSeconds } from '../commands';
+
+describe('mapParallel', () => {
+  it('executes all generated commands in parallel', () => {
+    const items = [{ x: 1 }, { x: 2 }, { x: 3 }, { x: 4 }];
+    const queue = new CommandQueue();
+    queue.enqueue(
+      mapParallel(items, item =>
+        sequence(waitForSeconds(1), () => {
+          item.x++;
+        })
+      )
+    );
+    queue.update(0.5);
+    expect(items).toEqual([{ x: 1 }, { x: 2 }, { x: 3 }, { x: 4 }]);
+    queue.update(0.5);
+    expect(items).toEqual([{ x: 2 }, { x: 3 }, { x: 4 }, { x: 5 }]);
+  });
+
+  it('skips undefined return values', () => {
+    const items = [{ x: 1 }, { x: 2 }, { x: 3 }, { x: 4 }];
+    const queue = new CommandQueue();
+    queue.enqueue(
+      mapParallel(items, (item, index) => {
+        if (index % 2 === 0) {
+          return undefined;
+        }
+        return sequence(waitForSeconds(1), () => {
+          item.x++;
+        });
+      })
+    );
+    queue.update(0.5);
+    expect(items).toEqual([{ x: 1 }, { x: 2 }, { x: 3 }, { x: 4 }]);
+    queue.update(0.5);
+    expect(items).toEqual([{ x: 1 }, { x: 3 }, { x: 3 }, { x: 5 }]);
+  });
+});
+
+describe('mapSequential', () => {
+  it('executes all generated commands in sequence', () => {
+    const items = [{ x: 1 }, { x: 2 }, { x: 3 }, { x: 4 }];
+    const queue = new CommandQueue();
+    queue.enqueue(
+      mapSequential(items, item =>
+        sequence(waitForSeconds(1), () => {
+          item.x++;
+        })
+      )
+    );
+    queue.update(1);
+    expect(items).toEqual([{ x: 2 }, { x: 2 }, { x: 3 }, { x: 4 }]);
+    queue.update(1);
+    expect(items).toEqual([{ x: 2 }, { x: 3 }, { x: 3 }, { x: 4 }]);
+    queue.update(2);
+    expect(items).toEqual([{ x: 2 }, { x: 3 }, { x: 4 }, { x: 5 }]);
+  });
+});

src/core/commands/functional.ts

@@ -0,0 +1,25 @@
+import { CommandFactory, Command, parallel, sequence } from '../commands';
+
+export function mapParallel<T>(items: Iterable<T>, factory: (item: T, index: number) => Command | undefined): Command {
+  return parallel(...mapToCommands(items, factory));
+}
+
+export function mapSequential<T>(
+  items: Iterable<T>,
+  factory: (item: T, index: number) => Command | undefined
+): Command {
+  return sequence(...mapToCommands(items, factory));
+}
+
+function mapToCommands<T>(items: Iterable<T>, factory: (item: T, index: number) => Command | undefined): Command[] {
+  const commands = [];
+  let index = 0;
+  for (const item of items) {
+    const command = factory(item, index);
+    ++index;
+    if (command !== undefined) {
+      commands.push(command);
+    }
+  }
+  return commands;
+}