brewman/overlord/src/app/purchase-entries/purchase-entries-datasource.ts
tanshu af343cb7f9 All datasources done. Now to wire them up in the components.
Plus ElementRefs are now optional as they cannot be initialized
2020-11-23 10:25:53 +05:30

72 lines
2.3 KiB
TypeScript

import { DataSource } from '@angular/cdk/collections';
import { EventEmitter } from '@angular/core';
import { MatPaginator, PageEvent } from '@angular/material/paginator';
import { MatSort, Sort } from '@angular/material/sort';
import { merge, Observable, of as observableOf } from 'rxjs';
import { map } from 'rxjs/operators';
import { PurchaseEntriesItem } from './purchase-entries-item';
/** Simple sort comparator for example ID/Name columns (for client-side sorting). */
function compare(a: string | number, b: string | number, isAsc: boolean) {
return (a < b ? -1 : 1) * (isAsc ? 1 : -1);
}
export class PurchaseEntriesDataSource extends DataSource<PurchaseEntriesItem> {
constructor(
public data: PurchaseEntriesItem[],
private paginator?: MatPaginator,
private sort?: MatSort,
) {
super();
}
connect(): Observable<PurchaseEntriesItem[]> {
const dataMutations: (
| Observable<PurchaseEntriesItem[]>
| EventEmitter<PageEvent>
| EventEmitter<Sort>
)[] = [observableOf(this.data)];
if (this.paginator) dataMutations.push((this.paginator as MatPaginator).page);
if (this.sort) dataMutations.push((this.sort as MatSort).sortChange);
// Set the paginators length
if (this.paginator) this.paginator.length = this.data.length;
return merge(...dataMutations).pipe(
map(() => this.getPagedData(this.getSortedData([...this.data]))),
);
}
disconnect() {}
private getPagedData(data: PurchaseEntriesItem[]) {
if (this.paginator === undefined) return data;
const startIndex = this.paginator.pageIndex * this.paginator.pageSize;
return data.splice(startIndex, this.paginator.pageSize);
}
private getSortedData(data: PurchaseEntriesItem[]) {
if (this.sort === undefined) return data;
if (!this.sort.active || this.sort.direction === '') {
return data;
}
const sort = this.sort as MatSort;
return data.sort((a, b) => {
const isAsc = sort.direction === 'asc';
switch (sort.active) {
case 'date':
return compare(a.date, b.date, isAsc);
case 'supplier':
return compare(a.supplier, b.supplier, isAsc);
case 'product':
return compare(a.product, b.product, isAsc);
case 'amount':
return compare(+a.amount, +b.amount, isAsc);
default:
return 0;
}
});
}
}