add applied filter string func

src/models/itemFilterData.ts

@@ -19,6 +19,20 @@ export class ItemFilterData {
   displayOptions(): Option[] {
     return this.options
   }
+
+  labelForValue(value: string) {
+    return this.displayOptions().find((opt: Option) => {
+      return opt.value === value
+    })?.label
+  }
+
+  labelsForConcatenatedValues(values: string) {
+    return Array.from(
+      new Set(
+        values.split(",").map((val: string) => `'${this.labelForValue(val)}'`)
+      )
+    ).join(", ")
+  }
 }
 
 export class LocationFilterData extends ItemFilterData {

src/utils/itemFilterUtils.ts

@@ -1,4 +1,5 @@
 /* eslint-disable @typescript-eslint/naming-convention */
+import type { ItemFilterData } from "../models/itemFilterData"
 import type { AppliedFilters } from "../types/filterTypes"
 
 export const isRecapLocation = (loc: string) => {
@@ -48,3 +49,28 @@ export const buildItemFilterQueryParams = (
   const query = encodeURI(`?${location_query}${format_query}${status_query}`)
   return query.length > 3 ? query : ""
 }
+
+export const buildAppliedFiltersString = (
+  query: BibPageQueryParams,
+  numItems = 20,
+  itemAggs: ItemFilterData[]
+) => {
+  const items = `Item${numItems === 1 ? "" : "s"}`
+  if (Object.keys(query).length === 0) return `${numItems} ${items}`
+  const num = numItems === 0 ? "No" : numItems
+  const numMatchingItems = `${num} ${items} Matching `
+  const filters = Object.keys(query)
+    .map((field: string) => {
+      const queryPerField = query[field]
+      if (queryPerField) {
+        const fieldAggregations = itemAggs.find(
+          (agg: ItemFilterData) => agg.field === field.substring(5)
+        )
+        const labels =
+          fieldAggregations.labelsForConcatenatedValues(queryPerField)
+        return field.substring(5) + ": " + labels
+      }
+    })
+    .filter((filter) => filter)
+  return numMatchingItems + "Filtered by " + filters.join(", ")
+}

src/utils/utilsTests/itemFilterUtils.test.tsx

@@ -3,7 +3,10 @@ import {
   combineRecapLocations,
   parseItemFilterQueryParams,
   buildItemFilterQueryParams,
+  buildAppliedFiltersString,
 } from "../itemFilterUtils"
+import testAggregations from "../../../__test__/fixtures/testAggregations"
+import { ItemFilterData } from "../../models/itemFilterData"
 
 describe("Item Filter Utils", () => {
   describe("isRecapLocation", () => {
@@ -86,4 +89,50 @@ describe("Item Filter Utils", () => {
       )
     })
   })
+
+  describe("buildAppliedFiltersString", () => {
+    const query = {
+      item_location: "loc:rc2ma,loc:rcma2",
+      item_status: "status:a",
+      item_format: "Text",
+    }
+    const aggs = testAggregations.map((agg) => new ItemFilterData(agg))
+    it("can handle no filters", () => {
+      expect(buildAppliedFiltersString({}, 30, [])).toBe("30 Items")
+    })
+    it("no items with filters", () => {
+      const query = {
+        item_location: "loc:rc2ma,loc:rcma2",
+        item_status: "status:a",
+        item_format: "Text",
+      }
+      expect(buildAppliedFiltersString(query, 0, aggs)).toBe(
+        "No Items Matching Filtered by location: 'Offsite', status: 'Available', format: 'Text'"
+      )
+    })
+    it("some items no filters", () => {
+      expect(buildAppliedFiltersString({}, 5, aggs)).toBe("5 Items")
+    })
+    it("some items with filters", () => {
+      expect(buildAppliedFiltersString(query, 5, aggs)).toBe(
+        "5 Items Matching Filtered by location: 'Offsite', status: 'Available', format: 'Text'"
+      )
+    })
+    it("one item with filters", () => {
+      expect(buildAppliedFiltersString(query, 1, aggs)).toBe(
+        "1 Item Matching Filtered by location: 'Offsite', status: 'Available', format: 'Text'"
+      )
+    })
+    it("some items one filter", () => {
+      expect(
+        buildAppliedFiltersString(
+          { item_status: "status:a,status:na" },
+          5,
+          aggs
+        )
+      ).toBe(
+        "5 Items Matching Filtered by status: 'Available', 'Not available'"
+      )
+    })
+  })
 })