feat: calculate layer

packages/utils/dag.test.js

@@ -0,0 +1,50 @@
+import DAG from './dag.js'
+
+describe('dag', () => {
+  const data = [
+    {
+      _id: 'helloworld',
+      title: 'Hello, Linux World!',
+      requirements: [],
+    },
+    {
+      _id: 'spell',
+      title: 'Learn to spell',
+      requirements: ['helloworld'],
+    },
+    {
+      _id: 'discover',
+      title: 'Discover the World!',
+      requirements: ['spell'],
+    },
+    {
+      _id: 'read',
+      title: 'Read the File',
+      requirements: ['spell'],
+    },
+    {
+      _id: 'remove',
+      requirements: ['read', 'discover'],
+    },
+    {
+      _id: 'move',
+      requirements: ['helloworld'],
+    },
+    {
+      _id: 'copy',
+      requirements: ['remove', 'move'],
+    },
+  ]
+
+  it('should set layers', () => {
+    const dag = new DAG(data)
+    dag.format()
+    expect(dag.get('helloworld').layer).toBe(1)
+    expect(dag.get('spell').layer).toBe(2)
+    expect(dag.get('move').layer).toBe(2)
+    expect(dag.get('read').layer).toBe(3)
+    expect(dag.get('discover').layer).toBe(3)
+    expect(dag.get('remove').layer).toBe(4)
+    expect(dag.get('copy').layer).toBe(5)
+  })
+})