Kanban Method

// Kanban Board Data Model
interface KanbanBoard {
  id: string;
  name: string;
  columns: KanbanColumn[];
  policies: BoardPolicy[];
  metrics: FlowMetrics;
}

interface KanbanColumn {
  id: string;
  name: string;
  wipLimit: number;
  currentWIP: number;
  items: KanbanItem[];
  subColumns?: { name: string; items: KanbanItem[] }[]; // e.g., "Doing" | "Done"
}

interface KanbanItem {
  id: string;
  title: string;
  type: 'feature' | 'bug' | 'improvement' | 'urgent';
  priority: 'expedite' | 'high' | 'medium' | 'low';
  assignee: string | null;
  createdDate: Date;
  startedDate: Date | null;
  completedDate: Date | null;
  blockedSince: Date | null;
  tags: string[];
  size: 'S' | 'M' | 'L' | 'XL';
}

interface BoardPolicy {
  column: string;
  rules: string[];
}

interface FlowMetrics {
  averageLeadTime: number; // days
  averageCycleTime: number; // days
  throughput: number; // items per week
  wipAge: { itemId: string; age: number }[]; // how long items have been in WIP
}

// Example Kanban board for a dev team
const devBoard: KanbanBoard = {
  id: 'board-1',
  name: 'Platform Team',
  columns: [
    {
      id: 'col-1',
      name: 'Backlog',
      wipLimit: 20,
      currentWIP: 15,
      items: [],
    },
    {
      id: 'col-2',
      name: 'Ready',
      wipLimit: 5,
      currentWIP: 3,
      items: [],
    },
    {
      id: 'col-3',
      name: 'In Development',
      wipLimit: 4,
      currentWIP: 4,
      items: [],
      subColumns: [
        { name: 'Coding', items: [] },
        { name: 'Code Review', items: [] }
      ]
    },
    {
      id: 'col-4',
      name: 'Testing',
      wipLimit: 3,
      currentWIP: 2,
      items: [],
    },
    {
      id: 'col-5',
      name: 'Done',
      wipLimit: Infinity,
      currentWIP: 42,
      items: [],
    }
  ],
  policies: [
    {
      column: 'Ready',
      rules: [
        'Item has clear acceptance criteria',
        'Dependencies are resolved',
        'Item is estimated (S/M/L/XL)'
      ]
    },
    {
      column: 'In Development',
      rules: [
        'Developer has pulled the item (not assigned)',
        'Branch created from main',
        'Move to Code Review when PR is opened'
      ]
    },
    {
      column: 'Testing',
      rules: [
        'All automated tests pass',
        'Manual testing for UI changes',
        'Move to Done when QA approves'
      ]
    }
  ],
  metrics: {
    averageLeadTime: 8.5,
    averageCycleTime: 4.2,
    throughput: 12,
    wipAge: []
  }
};

// Calculate flow efficiency
function calculateFlowEfficiency(
  activeTime: number,
  totalLeadTime: number
): number {
  // Flow efficiency = active time / total lead time
  // Typical teams: 15-40%, World class: 40%+
  return (activeTime / totalLeadTime) * 100;
}

// Little's Law calculator
function predictLeadTime(wip: number, throughput: number): number {
  // Lead Time = WIP / Throughput
  return wip / throughput;
}