@angular/cdk
Version:
Angular Material Component Development Kit
227 lines (224 loc) • 7.96 kB
JavaScript
import { Subject } from 'rxjs';
/**
* Class to be used to power selecting one or more options from a list.
*/
class SelectionModel {
_multiple;
_emitChanges;
compareWith;
/** Currently-selected values. */
_selection = new Set();
/** Keeps track of the deselected options that haven't been emitted by the change event. */
_deselectedToEmit = [];
/** Keeps track of the selected options that haven't been emitted by the change event. */
_selectedToEmit = [];
/** Cache for the array value of the selected items. */
_selected;
/** Selected values. */
get selected() {
if (!this._selected) {
this._selected = Array.from(this._selection.values());
}
return this._selected;
}
/** Event emitted when the value has changed. */
changed = new Subject();
constructor(_multiple = false, initiallySelectedValues, _emitChanges = true, compareWith) {
this._multiple = _multiple;
this._emitChanges = _emitChanges;
this.compareWith = compareWith;
if (initiallySelectedValues && initiallySelectedValues.length) {
if (_multiple) {
initiallySelectedValues.forEach(value => this._markSelected(value));
}
else {
this._markSelected(initiallySelectedValues[0]);
}
// Clear the array in order to avoid firing the change event for preselected values.
this._selectedToEmit.length = 0;
}
}
/**
* Selects a value or an array of values.
* @param values The values to select
* @return Whether the selection changed as a result of this call
* @breaking-change 16.0.0 make return type boolean
*/
select(...values) {
this._verifyValueAssignment(values);
values.forEach(value => this._markSelected(value));
const changed = this._hasQueuedChanges();
this._emitChangeEvent();
return changed;
}
/**
* Deselects a value or an array of values.
* @param values The values to deselect
* @return Whether the selection changed as a result of this call
* @breaking-change 16.0.0 make return type boolean
*/
deselect(...values) {
this._verifyValueAssignment(values);
values.forEach(value => this._unmarkSelected(value));
const changed = this._hasQueuedChanges();
this._emitChangeEvent();
return changed;
}
/**
* Sets the selected values
* @param values The new selected values
* @return Whether the selection changed as a result of this call
* @breaking-change 16.0.0 make return type boolean
*/
setSelection(...values) {
this._verifyValueAssignment(values);
const oldValues = this.selected;
const newSelectedSet = new Set(values.map(value => this._getConcreteValue(value)));
values.forEach(value => this._markSelected(value));
oldValues
.filter(value => !newSelectedSet.has(this._getConcreteValue(value, newSelectedSet)))
.forEach(value => this._unmarkSelected(value));
const changed = this._hasQueuedChanges();
this._emitChangeEvent();
return changed;
}
/**
* Toggles a value between selected and deselected.
* @param value The value to toggle
* @return Whether the selection changed as a result of this call
* @breaking-change 16.0.0 make return type boolean
*/
toggle(value) {
return this.isSelected(value) ? this.deselect(value) : this.select(value);
}
/**
* Clears all of the selected values.
* @param flushEvent Whether to flush the changes in an event.
* If false, the changes to the selection will be flushed along with the next event.
* @return Whether the selection changed as a result of this call
* @breaking-change 16.0.0 make return type boolean
*/
clear(flushEvent = true) {
this._unmarkAll();
const changed = this._hasQueuedChanges();
if (flushEvent) {
this._emitChangeEvent();
}
return changed;
}
/**
* Determines whether a value is selected.
*/
isSelected(value) {
return this._selection.has(this._getConcreteValue(value));
}
/**
* Determines whether the model does not have a value.
*/
isEmpty() {
return this._selection.size === 0;
}
/**
* Determines whether the model has a value.
*/
hasValue() {
return !this.isEmpty();
}
/**
* Sorts the selected values based on a predicate function.
*/
sort(predicate) {
if (this._multiple && this.selected) {
this._selected.sort(predicate);
}
}
/**
* Gets whether multiple values can be selected.
*/
isMultipleSelection() {
return this._multiple;
}
/** Emits a change event and clears the records of selected and deselected values. */
_emitChangeEvent() {
// Clear the selected values so they can be re-cached.
this._selected = null;
if (this._selectedToEmit.length || this._deselectedToEmit.length) {
this.changed.next({
source: this,
added: this._selectedToEmit,
removed: this._deselectedToEmit,
});
this._deselectedToEmit = [];
this._selectedToEmit = [];
}
}
/** Selects a value. */
_markSelected(value) {
value = this._getConcreteValue(value);
if (!this.isSelected(value)) {
if (!this._multiple) {
this._unmarkAll();
}
if (!this.isSelected(value)) {
this._selection.add(value);
}
if (this._emitChanges) {
this._selectedToEmit.push(value);
}
}
}
/** Deselects a value. */
_unmarkSelected(value) {
value = this._getConcreteValue(value);
if (this.isSelected(value)) {
this._selection.delete(value);
if (this._emitChanges) {
this._deselectedToEmit.push(value);
}
}
}
/** Clears out the selected values. */
_unmarkAll() {
if (!this.isEmpty()) {
this._selection.forEach(value => this._unmarkSelected(value));
}
}
/**
* Verifies the value assignment and throws an error if the specified value array is
* including multiple values while the selection model is not supporting multiple values.
*/
_verifyValueAssignment(values) {
if (values.length > 1 && !this._multiple && (typeof ngDevMode === 'undefined' || ngDevMode)) {
throw getMultipleValuesInSingleSelectionError();
}
}
/** Whether there are queued up change to be emitted. */
_hasQueuedChanges() {
return !!(this._deselectedToEmit.length || this._selectedToEmit.length);
}
/** Returns a value that is comparable to inputValue by applying compareWith function, returns the same inputValue otherwise. */
_getConcreteValue(inputValue, selection) {
if (!this.compareWith) {
return inputValue;
}
else {
selection = selection ?? this._selection;
for (let selectedValue of selection) {
if (this.compareWith(inputValue, selectedValue)) {
return selectedValue;
}
}
return inputValue;
}
}
}
/**
* Returns an error that reports that multiple values are passed into a selection model
* with a single value.
* @docs-private
*/
function getMultipleValuesInSingleSelectionError() {
return Error('Cannot pass multiple values into SelectionModel with single-value mode.');
}
export { SelectionModel as S, getMultipleValuesInSingleSelectionError as g };
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