src/components/metadata/metadata.component.ts

@@ -20,8 +20,8 @@ export class MetadataComponent {
 
   constructor(metaService: MetaService, private queryService: QueryService) {
     combineLatest({
-      meta: metaService.Data,
-      query: queryService.Query,
+      meta: metaService.Data$,
+      query: queryService.Query$,
     }).subscribe((d: { meta: Partial<TreeNode>[]; query: Query }) => {
       const inuse = d.query.fields;
       const expanded = this.getExpanded(this.node);

src/components/query/query.component.ts

@@ -8,9 +8,14 @@ import {
   faArrowDown,
   faArrowUp,
   faRemove,
+  faSort,
+  faSortAsc,
+  faSortDesc,
+  faSortDown,
 } from '@fortawesome/free-solid-svg-icons';
 import { ExecuteService } from '../../services/execute.service';
 import { Header } from '../../models/header';
+import { SORT } from '../../enums/sort';
 
 @Component({
   selector: 'fbi-query',
@@ -26,8 +31,11 @@ export class QueryComponent {
     private queryService: QueryService,
     executeService: ExecuteService
   ) {
-    queryService.Query.subscribe((query: Query) => {
-      executeService.headers(query).subscribe((headers: Header[]) => {
+    queryService.Query$.subscribe((query: Query) => {
+      const headers = executeService.headers(query);
+      const fields = this.getFields(query, headers);
+      const filters = this.getFilters(query, headers);
+      const sort = this.getSorts(query, headers);
       this.node = new TreeNode({
         hidden: true,
         expanded: true,
@@ -36,9 +44,51 @@ export class QueryComponent {
             label: 'Fields',
             leaf: false,
             expanded: true,
-              children: (query?.fields ?? []).map(
+            children: fields,
+          },
+          {
+            label: 'Filters',
+            expanded: true,
+            leaf: false,
+            children: filters,
+          },
+          {
+            label: 'Sort',
+            expanded: true,
+            leaf: false,
+            children: sort,
+          },
+        ] as TreeNode[],
+      });
+    });
+  }
+
+  onActionClick(event: { action: Action; node: TreeNode }): void {
+    const data = event.action.data as ActionData;
+    switch (data.cmd) {
+      case ACTIONS.REMOVE:
+        this.queryService.remove(event.node.data);
+        break;
+      case ACTIONS.UP:
+      case ACTIONS.DOWN:
+        this.queryService.add(event.node.data, data.data);
+        break;
+      case ACTIONS.SORTASC:
+      case ACTIONS.SORTDSC:
+      case ACTIONS.SORTDEL:
+        this.queryService.sort(data.data);
+        break;
+    }
+  }
+
+  private getFields(query: Query, headers: Header[]): Partial<TreeNode>[] {
+    return (query?.fields ?? []).map(
       (field: string, index: number, array: string[]) => {
+        const sort = query?.sort?.field ?? '';
+        const sdir = query?.sort?.dir ?? SORT.NONE;
+
         const actions = [];
+        // move
         if (index !== 0) {
           actions.push({
             label: 'Move Up',
@@ -53,6 +103,41 @@ export class QueryComponent {
             data: { cmd: ACTIONS.DOWN, data: index + 1 },
           });
         }
+
+        // sort
+        if (sort === field) {
+          switch (sdir) {
+            case SORT.ASC:
+              actions.push({
+                label: 'Sort Dsc',
+                icon: faSortDown,
+                data: { cmd: ACTIONS.SORTDSC, data: field },
+              });
+              break;
+            case SORT.DSC:
+              actions.push({
+                label: 'Clear Sort',
+                icon: faSort,
+                data: { cmd: ACTIONS.SORTDEL, data: field },
+              });
+              break;
+            default:
+              actions.push({
+                label: 'Sort Asc',
+                icon: faSortAsc,
+                data: { cmd: ACTIONS.SORTASC, data: field },
+              });
+              break;
+          }
+        } else {
+          actions.push({
+            label: 'Sort Asc',
+            icon: faSortAsc,
+            data: { cmd: ACTIONS.SORTASC, data: field },
+          });
+        }
+
+        // remove
         actions.push({
           label: 'Remove',
           icon: faRemove,
@@ -60,8 +145,8 @@ export class QueryComponent {
         });
 
         const label =
-                    headers.find((header: Header) => header.source === field)
-                      ?.label ?? 'unknown';
+          headers.find((header: Header) => header.source === field)?.label ??
+          'unknown';
 
         return {
           label: label,
@@ -69,28 +154,45 @@ export class QueryComponent {
           actions: actions,
         };
       }
-              ),
-            },
-            { label: 'Filters', expanded: true, leaf: false },
-          ] as TreeNode[],
-        });
+    );
+  }
+
+  private getFilters(query: Query, headers: Header[]): Partial<TreeNode>[] {
+    return [];
+  }
+
+  private getSorts(query: Query, headers: Header[]): Partial<TreeNode>[] {
+    const result: Partial<TreeNode>[] = [];
+
+    if (query?.sort?.isValid?.()) {
+      const s = query.sort;
+      const label =
+        headers.find((header: Header) => header.source === s.field)?.label ??
+        'unknown';
+      const actions = [];
+
+      if (s.dir === SORT.ASC) {
+        actions.push({
+          label: 'Sort Dsc',
+          icon: faSortDesc,
+          data: { cmd: ACTIONS.SORTDSC, data: s.field },
         });
+      } else if (s.dir === SORT.DSC) {
+        actions.push({
+          label: 'Clear Sort',
+          icon: faSort,
+          data: { cmd: ACTIONS.SORTDEL, data: s.field },
         });
       }
 
-  onActionClick(event: { action: Action; node: TreeNode }): void {
-    const data = event.action.data as ActionData;
-    switch (data.cmd) {
-      case ACTIONS.REMOVE:
-        this.queryService.remove(event.node.data);
-        break;
-      case ACTIONS.UP:
-        this.queryService.add(event.node.data, data.data);
-        break;
-      case ACTIONS.DOWN:
-        this.queryService.add(event.node.data, data.data);
-        break;
+      result.push({
+        label: label,
+        data: s.field,
+        actions: actions,
+      });
     }
+
+    return result;
   }
 }
 
@@ -98,6 +200,9 @@ enum ACTIONS {
   REMOVE = 'del',
   UP = 'up',
   DOWN = 'down',
+  SORTDSC = 'dsc',
+  SORTASC = 'asc',
+  SORTDEL = 'nne',
 }
 
 type ActionData = {

src/components/result/result.component.html

@@ -1 +1,5 @@
-<fbi-table [headers]="headers" [rows]="rows"></fbi-table>
+<fbi-table
+  [data]="data"
+  (page)="onPage($event)"
+  (sort)="onSort($event)"
+></fbi-table>

src/components/result/result.component.ts

@@ -4,9 +4,10 @@ import { TreeComponent } from '../tree/tree.component';
 import { QueryService } from '../../services/query.service';
 import { Query } from '../../models/query';
 import { ExecuteService } from '../../services/execute.service';
-import { forkJoin } from 'rxjs';
-import { Header } from '../../models/header';
 import { TableComponent } from '../table/table.component';
+import { Result } from '../../models/result';
+import { Header } from '../../models/header';
+import { Page } from '../../models/page';
 
 @Component({
   selector: 'fbi-result',
@@ -16,34 +17,43 @@ import { TableComponent } from '../table/table.component';
   styleUrl: './result.component.scss',
 })
 export class ResultComponent {
-  headers: Header[] = [];
-  rows: Record<string, any>[] = [];
+  data: Result = new Result({});
+
+  private query: Query = new Query({});
+  private page: Page = new Page({});
 
   constructor(
-    queryService: QueryService,
+    private queryService: QueryService,
     private executeService: ExecuteService
   ) {
     let last: string = '';
-    queryService.Query.subscribe((query: Query) => {
+    queryService.Query$.subscribe((query: Query) => {
       if (query.isValid()) {
         const current = query.toString();
         if (last !== current) {
-          this.load(query);
+          this.query = query;
+          this.page = new Page({});
+          this.load();
           last = current;
         }
       }
     });
   }
 
-  private load(query: Query): void {
-    forkJoin({
-      headers: this.executeService.headers(query),
-      data: this.executeService.data(query),
-    }).subscribe(
-      (result: { headers: Header[]; data: Record<string, any>[] }) => {
-        this.headers = result.headers;
-        this.rows = result.data;
+  private load(): void {
+    const query = new Query(this.query);
+    query.page = new Page(this.page);
+    this.executeService.data(query).subscribe((result: Result) => {
+      this.data = result;
+    });
   }
-    );
+
+  onPage(page: Page): void {
+    this.page = new Page(page);
+    this.load();
+  }
+
+  onSort(header: Header): void {
+    this.queryService.sort(header.source);
   }
 }

src/components/table/table.component.html

@@ -1,14 +1,59 @@
+@if (data.headers.length > 0) {
 <table>
+  <thead>
     <tr>
-    <th></th>
-    <th *ngFor="let h of headers">
+      <th class="spacer"></th>
+      @for (h of data.headers; track h) {
+      <th [title]="h.label">
         {{ h.label }}
+        <span
+          class="clickable"
+          [class.button]="h.sort !== SORT.NONE"
+          [class.unused]="h.sort === SORT.NONE"
+          (click)="onSort($event, h)"
+        >
+          @switch (h.sort) { @case (SORT.ASC) {
+          <fa-icon [icon]="faSortUp"></fa-icon>
+          } @case(SORT.DSC) {
+          <fa-icon [icon]="faSortDown"></fa-icon>
+          } @default {
+          <fa-icon [icon]="faSort"></fa-icon>
+          } }
+        </span>
       </th>
+      }
     </tr>
-  <tr *ngFor="let row of rows; index as i">
-    <td>{{ i }}</td>
-    <td *ngFor="let h of headers">
+  </thead>
+  <tbody>
+    @for (row of data.data; track row; let i = $index) {
+    <tr>
+      <td>
+        @if (data.page) {
+        {{ (data.page.page - 1) * data.page.size + i + 1 }}
+        } @else {
+        {{ i + 1 }}
+        }
+      </td>
+      @for (h of data.headers; track h) {
+      <td>
         {{ row[h.source] }}
       </td>
+      }
     </tr>
+    }
+  </tbody>
+  @if (data.page) {
+  <tfoot>
+    <tr>
+      <td [attr.colspan]="data.headers.length + 1">
+        <span>
+          Showing {{ (data.page.page - 1) * data.page.size + 1 }} to
+          {{ data.page.page * data.page.size }} of {{ data.total }}
+        </span>
+        <span> </span>
+      </td>
+    </tr>
+  </tfoot>
+  }
 </table>
+}

src/components/table/table.component.scss

@@ -0,0 +1,61 @@
+table {
+  border-collapse: collapse;
+}
+
+thead {
+  th {
+    border: 1px solid #ddd;
+    background-color: #eee;
+    text-align: left;
+    vertical-align: top;
+    margin: 2px;
+    padding: 0px 2px;
+  }
+
+  th.highlight {
+    background-color: #cdf;
+  }
+
+  .spacer {
+    border: none;
+    background-color: inherit;
+  }
+}
+
+tbody {
+  td {
+    border: 1px solid #ddd;
+    text-align: right;
+    padding: 2px;
+  }
+
+  td.highlight {
+    background-color: #def;
+  }
+
+  td:hover {
+    background-color: #eff;
+  }
+}
+
+tfoot {
+  td {
+    text-align: center;
+  }
+}
+
+.left {
+  text-align: left;
+}
+
+.unused {
+  color: #ddd;
+}
+
+.button {
+  color: #777;
+}
+
+.clickable {
+  cursor: pointer;
+}

src/components/table/table.component.ts

@@ -1,15 +1,41 @@
 import { CommonModule } from '@angular/common';
-import { Component, Input } from '@angular/core';
+import { Component, EventEmitter, Input, Output } from '@angular/core';
 import { Header } from '../../models/header';
+import {
+  faSort,
+  faSortDown,
+  faSortUp,
+} from '@fortawesome/free-solid-svg-icons';
+import { FontAwesomeModule } from '@fortawesome/angular-fontawesome';
+import { SORT } from '../../enums/sort';
+import { Result } from '../../models/result';
+import { Page } from '../../models/page';
 
 @Component({
   selector: 'fbi-table',
   standalone: true,
-  imports: [CommonModule],
+  imports: [CommonModule, FontAwesomeModule],
   templateUrl: './table.component.html',
   styleUrl: './table.component.scss',
 })
 export class TableComponent {
-  @Input() headers!: Header[];
-  @Input() rows!: Record<string, any>[];
+  @Input() data!: Result;
+
+  @Output() page = new EventEmitter<Page>();
+  @Output() sort = new EventEmitter<Header>();
+
+  faSortDown = faSortDown;
+  faSortUp = faSortUp;
+  faSort = faSort;
+  SORT = SORT;
+
+  onPage(event: MouseEvent): void {
+    event.stopPropagation();
+    this.page.emit();
+  }
+
+  onSort(event: MouseEvent, header: Header): void {
+    event.stopPropagation();
+    this.sort.emit(header);
+  }
 }

src/enums/milestone.ts

@@ -2,7 +2,9 @@ export enum Milestone {
   Cohort = 'cohort',
   Year = 'year',
   County = 'mcode',
+  CountyLabel = 'county',
   School = 'lcode',
+  SchoolLabel = 'school',
   Grade = 'grade',
   ELACount = 'ecount',
   ELAMean = 'emean',

src/enums/sort.ts

@@ -0,0 +1,5 @@
+export enum SORT {
+  NONE = 'none',
+  ASC = 'asc',
+  DSC = 'dsc',
+}

src/models/header.ts

@@ -1,9 +1,13 @@
+import { SORT } from '../enums/sort';
+
 export class Header {
   label: string;
   source: string;
+  sort: SORT;
 
   constructor(data: Partial<Header>) {
     this.label = data?.label ?? '';
     this.source = data?.source ?? '';
+    this.sort = data?.sort ?? SORT.NONE;
   }
 }

src/models/page.ts

@@ -1,13 +1,13 @@
 export class Page {
-  start: number;
-  limit: number;
+  page: number;
+  size: number;
 
   constructor(data: Partial<Page>) {
-    this.start = data?.start ?? 1;
-    this.limit = data?.limit ?? 20;
+    this.page = data?.page ?? 1;
+    this.size = data?.size ?? 20;
   }
 
   toString(): string {
-    return `(${this.start}:${this.limit})`;
+    return `${this.page}:${this.size}`;
   }
 }

src/models/query.ts

@@ -1,14 +1,17 @@
 import { Page } from './page';
+import { Sort } from './sort';
 
 export class Query {
   fields: string[];
   filter: string[];
-  page: Page;
+  sort: Sort;
+  page?: Page;
 
   constructor(data: Partial<Query>) {
     this.fields = data?.fields ?? [];
     this.filter = data?.filter ?? [];
-    this.page = new Page(data?.page ?? {});
+    this.sort = new Sort(data?.sort ?? {});
+    if (data?.page) this.page = new Page(data?.page);
   }
 
   isValid(): boolean {
@@ -16,8 +19,11 @@ export class Query {
   }
 
   toString(): string {
-    const fields = (this.fields ?? []).join(', ');
-    const filters = '';
-    return `${fields}${filters}`;
+    return [
+      this.fields.join(','),
+      '',
+      this.page?.toString(),
+      this.sort.toString(),
+    ].join(';');
   }
 }

src/models/result.ts

@@ -0,0 +1,16 @@
+import { Header } from './header';
+import { Page } from './page';
+
+export class Result {
+  headers: Header[];
+  data: Record<string, any>[];
+  total: number;
+  page?: Page;
+
+  constructor(data: Partial<Result>) {
+    this.headers = data?.headers ?? [];
+    this.data = data?.data ?? [];
+    this.total = data?.total ?? 0;
+    if (data?.page) this.page = new Page(data.page);
+  }
+}

src/models/sort.ts

@@ -0,0 +1,19 @@
+import { SORT } from '../enums/sort';
+
+export class Sort {
+  field: string;
+  dir: SORT;
+
+  constructor(data: Partial<Sort>) {
+    this.field = data?.field ?? '';
+    this.dir = data?.dir ?? SORT.NONE;
+  }
+
+  isValid(): boolean {
+    return this.field !== '' && this.dir !== SORT.NONE;
+  }
+
+  toString(): string {
+    return `${this.field}:${this.dir}`;
+  }
+}

src/services/data.service.ts

@@ -68,16 +68,29 @@ export class DataService {
             const data: Record<string, any>[] = [];
 
             (results?.data ?? []).forEach((record: Record<string, any>) => {
-              let code = fn(Csv.County_Code, record);
+              const code = fn(Csv.County_Code, record);
               // skip non-data rows on the csv
               if (isNaN(code)) return;
+              const county = fs(Csv.County_Code, record);
+
+              const county_label = fs(Csv.County_Label, record);
+              const school_label = fs(Csv.School_Label, record);
+              if (county_label === '' || school_label === '') return;
+
+              if (!this._counties.has(county)) {
+                this._counties.set(county, county_label);
+              }
+              const school = fs(Csv.School_Code, record);
+              if (!this._schools.has(school)) {
+                this._schools.set(school, school_label);
+              }
 
               const ms = {} as Record<string, any>;
               ms[Milestone.Year] = year;
               ms[Milestone.Grade] = grade;
               ms[Milestone.Cohort] = cohort;
-              ms[Milestone.County] = fs(Csv.County_Code, record);
-              ms[Milestone.School] = fs(Csv.School_Code, record);
+              ms[Milestone.County] = this._counties.get(county); //fs(Csv.County_Code, record);
+              ms[Milestone.School] = this._schools.get(school); //fs(Csv.School_Code, record);
               if (year !== 2020) {
                 ms[Milestone.ELACount] = fn(Csv.ELA_Count, record);
                 ms[Milestone.ELAMean] = fn(Csv.ELA_Mean, record);
@@ -106,12 +119,14 @@ export class DataService {
               }
               data.push(ms);
 
-              const county = fs(Csv.County_Code, record);
-              this._counties.set(county, fs(Csv.County_Label, record));
-              this._schools.set(
-                `${county}-${fs(Csv.School_Code, record)}`,
-                fs(Csv.School_Label, record)
-              );
+              // this._counties.set(
+              //   fs(Csv.County_Code, record),
+              //   fs(Csv.County_Label, record)
+              // );
+              // this._schools.set(
+              //   fs(Csv.School_Code, record),
+              //   fs(Csv.School_Label, record)
+              // );
             });
 
             if (year !== 2020) {

src/services/execute.service.ts

@@ -4,6 +4,8 @@ import { Query } from '../models/query';
 import { Observable, of, map, take } from 'rxjs';
 import { Header } from '../models/header';
 import { MetaService } from './meta.service';
+import { SORT } from '../enums/sort';
+import { Result } from '../models/result';
 
 @Injectable({ providedIn: 'root' })
 export class ExecuteService {
@@ -12,27 +14,36 @@ export class ExecuteService {
     private metaService: MetaService
   ) {}
 
-  headers(query: Query): Observable<Header[]> {
-    if (!query?.isValid()) return of([]);
+  headers(query: Query): Header[] {
+    if (!query?.isValid?.()) return [];
 
-    const fields = query.fields;
-    return this.metaService.Flat.pipe(
-      map((items: Header[]) =>
-        items
+    const fields = [...query.fields];
+    const sort = query.sort;
+
+    return this.metaService
+      .Flat()
       .filter((item: Header) => fields.includes(item.source))
       .sort(
         (a: Header, b: Header) =>
           fields.indexOf(a.source) - fields.indexOf(b.source)
       )
-      ),
-      take(1)
-    );
+      .map((item: Header) => {
+        if (item.source === sort.field) {
+          item.sort = sort.dir;
+        }
+        return item;
+      });
   }
 
-  data(query: Query): Observable<Record<string, any>[]> {
-    if (!query?.isValid()) return of([]);
+  data(query: Query): Observable<Result> {
+    if (!query?.isValid()) return of(new Result({}));
+    console.log(query.toString());
 
-    const fields = query.fields;
+    const fields = [...query.fields];
+    const page = query.page;
+    const sort = query.sort;
+
+    const headers = this.headers(query);
 
     return this.dataService.Data$.pipe(
       // apply filter
@@ -43,37 +54,47 @@ export class ExecuteService {
           return true;
         });
       }),
-      // apply fields
-      map((data: Record<string, any>[]) =>
-        data.map((i: Record<string, any>) => {
+      // apply fields, make unique
+      map((data: Record<string, any>[]) => {
+        let unique = new Map<string, Record<string, any>>();
+        data.forEach((i: Record<string, any>) => {
           const r = {} as Record<string, any>;
           fields.forEach((field: string) => (r[field] = i[field]));
-          return r;
-        })
-      ),
-      // make the data unique and apply paging
-      map((data: Record<string, any>[]) => {
-        let i = 0;
-        const result: Record<string, any>[] = [];
-        const page = query.page;
-
-        data.some((d: Record<string, any>) => {
-          const idx = result.findIndex((r: Record<string, any>) =>
-            fields
-              .map((field: string) => d[field] === r[field])
-              .reduce((acc, cur) => acc && cur, true)
-          );
-
-          // if this element has not been seen before, add it to the results we care about.
-          if (idx < 0) {
-            result.push(d);
-            ++i;
-          }
-          return i >= page.start + page.limit;
+          const key = fields.map((field: string) => i[field]).join(':');
+          unique.set(key, r);
         });
-
-        return result.slice(page.start, page.start + page.limit);
+        return [...unique].map(([name, value]) => value);
       }),
+      // sort
+      map((data: Record<string, any>[]) => {
+        if (!sort.isValid()) return data;
+        const field = sort.field;
+
+        if (!fields.includes(field)) {
+        } else if (sort.dir === SORT.ASC) {
+          return data.sort((a: Record<string, any>, b: Record<string, any>) =>
+            a[field] > b[field] ? 1 : -1
+          );
+        } else if (sort.dir === SORT.DSC) {
+          return data.sort((a: Record<string, any>, b: Record<string, any>) =>
+            a[field] < b[field] ? 1 : -1
+          );
+        }
+        return data;
+      }),
+      // paging
+      map(
+        (data: Record<string, any>[]) =>
+          new Result({
+            headers: headers,
+            data: page
+              ? data.slice((page.page - 1) * page.size, page.page * page.size)
+              : data,
+            page: page,
+            total: data.length,
+          })
+          
+      ),
       // force it to close
       take(1)
     );

src/services/meta.service.ts

@@ -76,35 +76,54 @@ export class MetaService {
         { data: Milestone.Soc3, label: 'Advanced Learner %' },
       ],
     },
-  ];
-  private subject = new ReplaySubject<Partial<TreeNode>[]>(1);
-  readonly Data = this.subject.asObservable();
-  readonly Flat = this.subject.asObservable().pipe(
-    map((data: Partial<TreeNode>[]) => {
-      const recurse = (path: string, item: Partial<TreeNode>): Header[] => {
-        const result = [];
+  ] as Partial<TreeNode>[];
+
+  private subject = new ReplaySubject<TreeNode[]>(1);
+  readonly Data$ = this.subject
+    .asObservable()
+    .pipe(
+      map((items: TreeNode[]) =>
+        items.map((item: TreeNode) => new TreeNode(item))
+      )
+    );
+  // readonly Flat$ = this.subject.asObservable().pipe(
+  //   map((data: TreeNode[]) => {
+  //     const result: Header[] = [];
+  //     data.forEach((item: TreeNode) => result.push(...this.flatten('', item)));
+  //     return result;
+  //   })
+  // );
+
+  // readonly Data = () =>
+  //   this.data.map((item: Partial<TreeNode>) => new TreeNode(item));
+  readonly Flat = () => {
+    const result: Header[] = [];
+    this.data.forEach((item: Partial<TreeNode>) =>
+      result.push(...this.flatten('', item))
+    );
+    return result;
+  };
+
+  constructor() {
+    this.subject.next(
+      this.data.map((item: Partial<TreeNode>) => new TreeNode(item))
+    );
+  }
+
+  private flatten(path: string, item: Partial<TreeNode>): Header[] {
+    const result: Header[] = [];
     const children = item?.children ?? [];
+
     if (children.length > 0) {
-          children.forEach((child: Partial<TreeNode>) => {
-            result.push(...recurse(`${path}${item.label}`, child));
-          });
+      children.forEach((child: Partial<TreeNode>) =>
+        result.push(...this.flatten(`${path}${item.label}`, child))
+      );
     } else {
       result.push(
         new Header({ source: item.data, label: `${path} - ${item.label}` })
       );
     }
-        return result;
-      };
 
-      const result: Header[] = [];
-      data.forEach((item: Partial<TreeNode>) =>
-        result.push(...recurse('', item))
-      );
     return result;
-    })
-  );
-
-  constructor() {
-    this.subject.next(this.data as Partial<TreeNode>[]);
   }
 }

src/services/query.service.ts

@@ -1,11 +1,13 @@
 import { BehaviorSubject } from 'rxjs';
 import { Query } from '../models/query';
 import { Injectable } from '@angular/core';
+import { Sort } from '../models/sort';
+import { SORT } from '../enums/sort';
 
 @Injectable({ providedIn: 'root' })
 export class QueryService {
   private querySubject = new BehaviorSubject<Query>(new Query({}));
-  readonly Query = this.querySubject.asObservable();
+  readonly Query$ = this.querySubject.asObservable();
 
   constructor() {}
 
@@ -21,4 +23,25 @@ export class QueryService {
     q.fields = q.fields.filter((f: string) => f !== field);
     this.querySubject.next(q);
   }
+
+  sort(field: string): void {
+    const q = new Query(this.querySubject.value);
+    const s = q.sort;
+    if (s.field === field) {
+      switch (s.dir) {
+        case SORT.ASC:
+          q.sort = new Sort({ field: field, dir: SORT.DSC });
+          break;
+        case SORT.DSC:
+          q.sort = new Sort({});
+          break;
+        default:
+          q.sort = new Sort({ field: field, dir: SORT.ASC });
+          break;
+      }
+    } else {
+      q.sort = new Sort({ field: field, dir: SORT.ASC });
+    }
+    this.querySubject.next(q);
+  }
 }