Add fruit shipping example (#2)

* Add fruit shipping example

* Improve fruit example

* Fix import

* Fix lint errors

---------

Co-authored-by: Sam Willis <[email protected]>

Author: KyleAMathews

packages/d2ts/examples/fruit-processed.ts

@@ -0,0 +1,230 @@
+import { MultiSet } from '../src/multiset'
+import { D2 } from '../src/index.js'
+import { map, reduce, consolidate, output } from '../src/operators/index.js'
+import { v } from '../src/order.js'
+import { MessageType } from '../src/types.js'
+
+type FruitOrder = {
+  name: string,
+  quantity: number,
+  shipping_id: string,
+  status: 'packed' | 'shipped' | 'delivered'
+}
+
+const graph = new D2({ initialFrontier: v(0) })
+const input = graph.newInput<FruitOrder>()
+
+// Track quantities by status
+const materializedStatus = new Map<string, number>();
+const materializedProcessed = new Map<string, number>();
+
+function showStatus() {
+  const obj = Object.fromEntries(materializedStatus.entries())
+  console.log('Counts by Status:')
+  console.log(JSON.stringify(obj, null, 2))
+}
+
+function showProcessed() {
+  const obj = Object.fromEntries(materializedProcessed.entries())
+  console.log('Fruit Processed:')
+  console.log(JSON.stringify(obj, null, 2))
+}
+
+input.pipe(
+  // debug('Raw Input'),
+  map((order) => [`${order.name}-${order.status}`, order.quantity] as [string, number]),
+  // debug('After Map'),
+  reduce((values) => {
+    // The reduce function receives an array of [quantity, diff] for each key
+    // `diff` being the change in number of occurrences of the specific quantity
+    // It is not aware of the key, just that everything it is receiving is for the same key
+    // Here we want to sum the quantity for each key, so a sum of num * diff
+    let count = 0
+    for (const [num, diff] of values) {
+      count += num * diff
+    }
+    return [[count, 1]]
+  }),
+  // debug('Status Totals'),
+  consolidate(),
+  output((msg) => {
+    if (msg.type === MessageType.DATA) {
+      const entries = msg.data.collection.getInner();
+      // The entreis are:
+      // key: {fruit-name}-{status}
+      // count: number of items in that status
+      // diff: 1 if adding a row, -1 if removing a row
+      for (const [[key, count], diff] of entries) {
+        if (diff > 0) {
+          materializedStatus.set(key, count)
+        } else if (diff < 0) {
+          materializedStatus.delete(key)
+        }
+      }
+    }
+  })
+)
+
+// Track total processed quantities regardless of status
+input.pipe(
+  // debug('Raw Input'),
+  map((order) => [order.name, order.quantity] as [string, number]),
+  // debug('After Map'),
+  reduce((values) => {
+    // Count the total number of each fruit processed
+    let count = 0
+    for (const [num, diff] of values) {
+      count += num * diff
+    }
+    return [[count, 1]]
+  }),
+  // debug('Total Processed'),
+  consolidate(),
+  output((msg) => {
+    if (msg.type === MessageType.DATA) {
+      const entries = msg.data.collection.getInner();
+      for (const [[key, count], diff] of entries) {
+        if (diff > 0) {
+          materializedProcessed.set(key, count)
+        } else if (diff < 0) {
+          materializedProcessed.delete(key)
+        }
+      }
+    }
+  })
+)
+
+graph.finalize()
+
+console.log('--------------------------------')
+
+// Initial packing of orders
+console.log('Sending initial orders')
+input.sendData(v(0), new MultiSet([
+  [{
+    name: 'apple',
+    quantity: 100,
+    shipping_id: 'A001',
+    status: 'packed'
+  }, 1],
+  [{
+    name: 'banana',
+    quantity: 150,
+    shipping_id: 'B001',
+    status: 'packed'
+  }, 1]
+]))
+
+input.sendFrontier(v(1)) // Send a frontier to set the new minimum version
+graph.step() // Step the graph to process the data
+// Show the materialized status and processed totals:
+showStatus()
+showProcessed()
+
+console.log('--------------------------------')
+
+// Ship 2 orders
+console.log('Shipping 2 orders')
+input.sendData(v(1), new MultiSet([
+  // Remove from packed status
+  [{
+    name: 'apple',
+    quantity: 100,
+    shipping_id: 'A001',
+    status: 'packed'
+  }, -1],
+  // Add to shipped status
+  [{
+    name: 'apple',
+    quantity: 100,
+    shipping_id: 'A001',
+    status: 'shipped'
+  }, 1],
+  
+  [{
+    name: 'banana',
+    quantity: 150,
+    shipping_id: 'B001',
+    status: 'packed'
+  }, -1],
+  [{
+    name: 'banana',
+    quantity: 150,
+    shipping_id: 'B001',
+    status: 'shipped'
+  }, 1]
+]))
+
+input.sendFrontier(v(2))
+graph.step()
+showStatus()
+showProcessed()
+
+console.log('--------------------------------')
+
+// One order arrives
+console.log('One order arrives')
+input.sendData(v(2), new MultiSet([
+  // Remove from shipped status
+  [{
+    name: 'apple',
+    quantity: 100,
+    shipping_id: 'A001',
+    status: 'shipped'
+  }, -1],
+  // Add to delivered status
+  [{
+    name: 'apple',
+    quantity: 100,
+    shipping_id: 'A001',
+    status: 'delivered'
+  }, 1]
+]))
+
+input.sendFrontier(v(3))
+graph.step()
+showStatus()
+showProcessed()
+
+console.log('--------------------------------')
+
+/*
+Output:
+--------------------------------
+Sending initial orders
+Counts by Status:
+{
+  "apple-packed": 100,
+  "banana-packed": 150
+}
+Fruit Processed:
+{
+  "apple": 100,
+  "banana": 150
+}
+--------------------------------
+Shipping 2 orders
+Counts by Status:
+{
+  "apple-shipped": 100,
+  "banana-shipped": 150
+}
+Fruit Processed:
+{
+  "apple": 100,
+  "banana": 150
+}
+--------------------------------
+One order arrives
+Counts by Status:
+{
+  "banana-shipped": 150,
+  "apple-delivered": 100
+}
+Fruit Processed:
+{
+  "apple": 100,
+  "banana": 150
+}
+--------------------------------
+*/