Adds a date selection model (#17363)

* Adds a date selection model

* Adds a date selection model

Author: xlou978

src/material/core/datetime/date-selection-model.ts

@@ -0,0 +1,136 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {DateAdapter} from '@angular/material/core';
+import {Subject, Observable} from 'rxjs';
+
+export abstract class MatDateSelectionModel<D> {
+  protected _valueChangesSubject = new Subject<void>();
+  valueChanges: Observable<void> = this._valueChangesSubject.asObservable();
+
+  constructor(protected readonly adapter: DateAdapter<D>) {}
+
+  destroy() {
+    this._valueChangesSubject.complete();
+  }
+
+  abstract add(date: D | null): void;
+  abstract isComplete(): boolean;
+  abstract isSame(other: MatDateSelectionModel<D>): boolean;
+  abstract isValid(): boolean;
+}
+
+export interface DateRange<D> {
+  start: D | null;
+  end: D | null;
+}
+
+/**
+ * Concrete implementation of a MatDateSelectionModel that holds a single date.
+ */
+export class MatSingleDateSelectionModel<D> extends MatDateSelectionModel<D> {
+  private _date: D | null = null;
+
+  constructor(adapter: DateAdapter<D>, date?: D | null) {
+    super(adapter);
+    this._date = date === undefined ? null : date;
+  }
+
+  add(date: D | null) {
+    this._date = date;
+    this._valueChangesSubject.next();
+  }
+
+  compareDate(other: MatSingleDateSelectionModel<D>) {
+    const date = this.asDate();
+    const otherDate = other.asDate();
+    if (date != null && otherDate != null) {
+      return this.adapter.compareDate(date, otherDate);
+    }
+    return date === otherDate;
+  }
+
+  isComplete() { return this._date != null; }
+
+  isSame(other: MatDateSelectionModel<D>): boolean {
+    return other instanceof MatSingleDateSelectionModel &&
+        this.adapter.sameDate(other.asDate(), this._date);
+  }
+
+  isValid(): boolean {
+    return this._date != null && this.adapter.isDateInstance(this._date) &&
+           this.adapter.isValid(this._date);
+  }
+
+  asDate(): D | null {
+    return this.isValid() ? this._date : null;
+  }
+}
+
+/**
+ * Concrete implementation of a MatDateSelectionModel that holds a date range, represented by
+ * a start date and an end date.
+ */
+export class MatRangeDateSelectionModel<D> extends MatDateSelectionModel<D> {
+  private _start: D | null = null;
+  private _end: D | null = null;
+
+  constructor(adapter: DateAdapter<D>, start?: D | null, end?: D | null) {
+    super(adapter);
+    this._start = start === undefined ? null : start;
+    this._end = end === undefined ? null : end;
+  }
+
+  /**
+   * Adds an additional date to the range. If no date is set thus far, it will set it to the
+   * beginning. If the beginning is set, it will set it to the end.
+   * If add is called on a complete selection, it will empty the selection and set it as the start.
+   */
+  add(date: D | null): void {
+    if (this._start == null) {
+      this._start = date;
+    } else if (this._end == null) {
+      this._end = date;
+    } else {
+      this._start = date;
+      this._end = null;
+    }
+
+    this._valueChangesSubject.next();
+  }
+
+  setRange(start: D | null, end: D | null) {
+    this._start = start;
+    this._end = end;
+  }
+
+  isComplete(): boolean {
+    return this._start != null && this._end != null;
+  }
+
+  isSame(other: MatDateSelectionModel<D>): boolean {
+    if (other instanceof MatRangeDateSelectionModel) {
+      const otherRange = other.asRange();
+      return this.adapter.sameDate(this._start, otherRange.start) &&
+             this.adapter.sameDate(this._end, otherRange.end);
+    }
+    return false;
+  }
+
+  isValid(): boolean {
+    return this._start != null && this._end != null &&
+        this.adapter.isValid(this._start!) && this.adapter.isValid(this._end!);
+  }
+
+  asRange(): DateRange<D> {
+    return {
+      start: this._start,
+      end: this._end,
+    };
+  }
+}

src/material/core/datetime/index.ts

@@ -17,6 +17,7 @@ export * from './date-adapter';
 export * from './date-formats';
 export * from './native-date-adapter';
 export * from './native-date-formats';
+export * from './date-selection-model';
 
 
 @NgModule({

tools/public_api_guard/material/core.d.ts

@@ -79,6 +79,11 @@ export declare abstract class DateAdapter<D> {
     abstract today(): D;
 }
 
+export interface DateRange<D> {
+    end: D | null;
+    start: D | null;
+}
+
 export declare const JAN = 0, FEB = 1, MAR = 2, APR = 3, MAY = 4, JUN = 5, JUL = 6, AUG = 7, SEP = 8, OCT = 9, NOV = 10, DEC = 11;
 
 export declare const defaultRippleAnimationConfig: {
@@ -213,6 +218,18 @@ export declare type MatDateFormats = {
     };
 };
 
+export declare abstract class MatDateSelectionModel<D> {
+    protected _valueChangesSubject: Subject<void>;
+    protected readonly adapter: DateAdapter<D>;
+    valueChanges: Observable<void>;
+    constructor(adapter: DateAdapter<D>);
+    abstract add(date: D | null): void;
+    destroy(): void;
+    abstract isComplete(): boolean;
+    abstract isSame(other: MatDateSelectionModel<D>): boolean;
+    abstract isValid(): boolean;
+}
+
 export declare const MATERIAL_SANITY_CHECKS: InjectionToken<SanityChecks>;
 
 export declare class MatLine {
@@ -289,6 +306,16 @@ export declare class MatPseudoCheckboxModule {
 
 export declare type MatPseudoCheckboxState = 'unchecked' | 'checked' | 'indeterminate';
 
+export declare class MatRangeDateSelectionModel<D> extends MatDateSelectionModel<D> {
+    constructor(adapter: DateAdapter<D>, start?: D | null, end?: D | null);
+    add(date: D | null): void;
+    asRange(): DateRange<D>;
+    isComplete(): boolean;
+    isSame(other: MatDateSelectionModel<D>): boolean;
+    isValid(): boolean;
+    setRange(start: D | null, end: D | null): void;
+}
+
 export declare class MatRipple implements OnInit, OnDestroy, RippleTarget {
     animation: RippleAnimationConfig;
     centered: boolean;
@@ -310,6 +337,16 @@ export declare class MatRipple implements OnInit, OnDestroy, RippleTarget {
 export declare class MatRippleModule {
 }
 
+export declare class MatSingleDateSelectionModel<D> extends MatDateSelectionModel<D> {
+    constructor(adapter: DateAdapter<D>, date?: D | null);
+    add(date: D | null): void;
+    asDate(): D | null;
+    compareDate(other: MatSingleDateSelectionModel<D>): number | boolean;
+    isComplete(): boolean;
+    isSame(other: MatDateSelectionModel<D>): boolean;
+    isValid(): boolean;
+}
+
 export declare const JAN = 0, FEB = 1, MAR = 2, APR = 3, MAY = 4, JUN = 5, JUL = 6, AUG = 7, SEP = 8, OCT = 9, NOV = 10, DEC = 11;
 
 export declare function mixinColor<T extends Constructor<HasElementRef>>(base: T, defaultColor?: ThemePalette): CanColorCtor & T;