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observablelist.ts
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/
observablelist.ts
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// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.
import {
ArrayExt,
ArrayIterator,
IIterator,
IterableOrArrayLike,
each,
toArray
} from '@lumino/algorithm';
import { IDisposable } from '@lumino/disposable';
import { ISignal, Signal } from '@lumino/signaling';
/**
* A list which can be observed for changes.
*/
export interface IObservableList<T> extends IDisposable {
/**
* A signal emitted when the list has changed.
*/
readonly changed: ISignal<this, IObservableList.IChangedArgs<T>>;
/**
* The type of this object.
*/
readonly type: 'List';
/**
* The length of the list.
*
* #### Notes
* This is a read-only property.
*/
length: number;
/**
* Create an iterator over the values in the list.
*
* @returns A new iterator starting at the front of the list.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* No changes.
*/
iter(): IIterator<T>;
/**
* Remove all values from the list.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* All current iterators are invalidated.
*/
clear(): void;
/**
* Get the value at the specified index.
*
* @param index - The positive integer index of interest.
*
* @returns The value at the specified index.
*
* #### Undefined Behavior
* An `index` which is non-integral or out of range.
*/
get(index: number): T;
/**
* Insert a value into the list at a specific index.
*
* @param index - The index at which to insert the value.
*
* @param value - The value to set at the specified index.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* No changes.
*
* #### Notes
* The `index` will be clamped to the bounds of the list.
*
* #### Undefined Behavior
* An `index` which is non-integral.
*/
insert(index: number, value: T): void;
/**
* Insert a set of items into the list at the specified index.
*
* @param index - The index at which to insert the values.
*
* @param values - The values to insert at the specified index.
*
* #### Complexity.
* Linear.
*
* #### Iterator Validity
* No changes.
*
* #### Notes
* The `index` will be clamped to the bounds of the list.
*
* #### Undefined Behavior.
* An `index` which is non-integral.
*/
insertAll(index: number, values: IterableOrArrayLike<T>): void;
/**
* Move a value from one index to another.
*
* @parm fromIndex - The index of the element to move.
*
* @param toIndex - The index to move the element to.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* Iterators pointing at the lesser of the `fromIndex` and the `toIndex`
* and beyond are invalidated.
*
* #### Undefined Behavior
* A `fromIndex` or a `toIndex` which is non-integral.
*/
move(fromIndex: number, toIndex: number): void;
/**
* Add a value to the back of the list.
*
* @param value - The value to add to the back of the list.
*
* @returns The new length of the list.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* No changes.
*/
push(value: T): number;
/**
* Push a set of values to the back of the list.
*
* @param values - An iterable or array-like set of values to add.
*
* @returns The new length of the list.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* No changes.
*/
pushAll(values: IterableOrArrayLike<T>): number;
/**
* Remove and return the value at a specific index.
*
* @param index - The index of the value of interest.
*
* @returns The value at the specified index, or `undefined` if the
* index is out of range.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* Iterators pointing at the removed value and beyond are invalidated.
*
* #### Undefined Behavior
* An `index` which is non-integral.
*/
remove(index: number): T | undefined;
/**
* Remove a range of items from the list.
*
* @param startIndex - The start index of the range to remove (inclusive).
*
* @param endIndex - The end index of the range to remove (exclusive).
*
* @returns The new length of the list.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* Iterators pointing to the first removed value and beyond are invalid.
*
* #### Undefined Behavior
* A `startIndex` or `endIndex` which is non-integral.
*/
removeRange(startIndex: number, endIndex: number): number;
/**
* Remove the first occurrence of a value from the list.
*
* @param value - The value of interest.
*
* @returns The index of the removed value, or `-1` if the value
* is not contained in the list.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* Iterators pointing at the removed value and beyond are invalidated.
*/
removeValue(value: T): number;
/**
* Set the value at the specified index.
*
* @param index - The positive integer index of interest.
*
* @param value - The value to set at the specified index.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* No changes.
*
* #### Undefined Behavior
* An `index` which is non-integral or out of range.
*/
set(index: number, value: T): void;
}
/**
* The namespace for IObservableList related interfaces.
*/
export namespace IObservableList {
/**
* The change types which occur on an observable list.
*/
export type ChangeType =
/**
* Item(s) were added to the list.
*/
| 'add'
/**
* An item was moved within the list.
*/
| 'move'
/**
* Item(s) were removed from the list.
*/
| 'remove'
/**
* An item was set in the list.
*/
| 'set';
/**
* The changed args object which is emitted by an observable list.
*/
export interface IChangedArgs<T> {
/**
* The type of change undergone by the vector.
*/
type: ChangeType;
/**
* The new index associated with the change.
*/
newIndex: number;
/**
* The new values associated with the change.
*
* #### Notes
* The values will be contiguous starting at the `newIndex`.
*/
newValues: T[];
/**
* The old index associated with the change.
*/
oldIndex: number;
/**
* The old values associated with the change.
*
* #### Notes
* The values will be contiguous starting at the `oldIndex`.
*/
oldValues: T[];
}
}
/**
* A concrete implementation of [[IObservableList]].
*/
export class ObservableList<T> implements IObservableList<T> {
/**
* Construct a new observable map.
*/
constructor(options: ObservableList.IOptions<T> = {}) {
if (options.values !== void 0) {
each(options.values, value => {
this._array.push(value);
});
}
this._itemCmp = options.itemCmp || Private.itemCmp;
}
/**
* The type of this object.
*/
get type(): 'List' {
return 'List';
}
/**
* A signal emitted when the list has changed.
*/
get changed(): ISignal<this, IObservableList.IChangedArgs<T>> {
return this._changed;
}
/**
* The length of the list.
*/
get length(): number {
return this._array.length;
}
/**
* Test whether the list has been disposed.
*/
get isDisposed(): boolean {
return this._isDisposed;
}
/**
* Dispose of the resources held by the list.
*/
dispose(): void {
if (this._isDisposed) {
return;
}
this._isDisposed = true;
Signal.clearData(this);
this.clear();
}
/**
* Create an iterator over the values in the list.
*
* @returns A new iterator starting at the front of the list.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* No changes.
*/
iter(): IIterator<T> {
return new ArrayIterator(this._array);
}
/**
* Get the value at the specified index.
*
* @param index - The positive integer index of interest.
*
* @returns The value at the specified index.
*
* #### Undefined Behavior
* An `index` which is non-integral or out of range.
*/
get(index: number): T {
return this._array[index];
}
/**
* Set the value at the specified index.
*
* @param index - The positive integer index of interest.
*
* @param value - The value to set at the specified index.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* No changes.
*
* #### Undefined Behavior
* An `index` which is non-integral or out of range.
*/
set(index: number, value: T): void {
const oldValue = this._array[index];
if (value === undefined) {
throw new Error('Cannot set an undefined item');
}
// Bail if the value does not change.
const itemCmp = this._itemCmp;
if (itemCmp(oldValue, value)) {
return;
}
this._array[index] = value;
this._changed.emit({
type: 'set',
oldIndex: index,
newIndex: index,
oldValues: [oldValue],
newValues: [value]
});
}
/**
* Add a value to the end of the list.
*
* @param value - The value to add to the end of the list.
*
* @returns The new length of the list.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* No changes.
*/
push(value: T): number {
const num = this._array.push(value);
this._changed.emit({
type: 'add',
oldIndex: -1,
newIndex: this.length - 1,
oldValues: [],
newValues: [value]
});
return num;
}
/**
* Insert a value into the list at a specific index.
*
* @param index - The index at which to insert the value.
*
* @param value - The value to set at the specified index.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* No changes.
*
* #### Notes
* The `index` will be clamped to the bounds of the list.
*
* #### Undefined Behavior
* An `index` which is non-integral.
*/
insert(index: number, value: T): void {
ArrayExt.insert(this._array, index, value);
this._changed.emit({
type: 'add',
oldIndex: -1,
newIndex: index,
oldValues: [],
newValues: [value]
});
}
/**
* Remove the first occurrence of a value from the list.
*
* @param value - The value of interest.
*
* @returns The index of the removed value, or `-1` if the value
* is not contained in the list.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* Iterators pointing at the removed value and beyond are invalidated.
*/
removeValue(value: T): number {
const itemCmp = this._itemCmp;
const index = ArrayExt.findFirstIndex(this._array, item => {
return itemCmp(item, value);
});
this.remove(index);
return index;
}
/**
* Remove and return the value at a specific index.
*
* @param index - The index of the value of interest.
*
* @returns The value at the specified index, or `undefined` if the
* index is out of range.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* Iterators pointing at the removed value and beyond are invalidated.
*
* #### Undefined Behavior
* An `index` which is non-integral.
*/
remove(index: number): T | undefined {
const value = ArrayExt.removeAt(this._array, index);
if (value === undefined) {
return;
}
this._changed.emit({
type: 'remove',
oldIndex: index,
newIndex: -1,
newValues: [],
oldValues: [value]
});
return value;
}
/**
* Remove all values from the list.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* All current iterators are invalidated.
*/
clear(): void {
const copy = this._array.slice();
this._array.length = 0;
this._changed.emit({
type: 'remove',
oldIndex: 0,
newIndex: 0,
newValues: [],
oldValues: copy
});
}
/**
* Move a value from one index to another.
*
* @parm fromIndex - The index of the element to move.
*
* @param toIndex - The index to move the element to.
*
* #### Complexity
* Constant.
*
* #### Iterator Validity
* Iterators pointing at the lesser of the `fromIndex` and the `toIndex`
* and beyond are invalidated.
*
* #### Undefined Behavior
* A `fromIndex` or a `toIndex` which is non-integral.
*/
move(fromIndex: number, toIndex: number): void {
if (this.length <= 1 || fromIndex === toIndex) {
return;
}
const values = [this._array[fromIndex]];
ArrayExt.move(this._array, fromIndex, toIndex);
this._changed.emit({
type: 'move',
oldIndex: fromIndex,
newIndex: toIndex,
oldValues: values,
newValues: values
});
}
/**
* Push a set of values to the back of the list.
*
* @param values - An iterable or array-like set of values to add.
*
* @returns The new length of the list.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* No changes.
*/
pushAll(values: IterableOrArrayLike<T>): number {
const newIndex = this.length;
each(values, value => {
this._array.push(value);
});
this._changed.emit({
type: 'add',
oldIndex: -1,
newIndex,
oldValues: [],
newValues: toArray(values)
});
return this.length;
}
/**
* Insert a set of items into the list at the specified index.
*
* @param index - The index at which to insert the values.
*
* @param values - The values to insert at the specified index.
*
* #### Complexity.
* Linear.
*
* #### Iterator Validity
* No changes.
*
* #### Notes
* The `index` will be clamped to the bounds of the list.
*
* #### Undefined Behavior.
* An `index` which is non-integral.
*/
insertAll(index: number, values: IterableOrArrayLike<T>): void {
const newIndex = index;
each(values, value => {
ArrayExt.insert(this._array, index++, value);
});
this._changed.emit({
type: 'add',
oldIndex: -1,
newIndex,
oldValues: [],
newValues: toArray(values)
});
}
/**
* Remove a range of items from the list.
*
* @param startIndex - The start index of the range to remove (inclusive).
*
* @param endIndex - The end index of the range to remove (exclusive).
*
* @returns The new length of the list.
*
* #### Complexity
* Linear.
*
* #### Iterator Validity
* Iterators pointing to the first removed value and beyond are invalid.
*
* #### Undefined Behavior
* A `startIndex` or `endIndex` which is non-integral.
*/
removeRange(startIndex: number, endIndex: number): number {
const oldValues = this._array.slice(startIndex, endIndex);
for (let i = startIndex; i < endIndex; i++) {
ArrayExt.removeAt(this._array, startIndex);
}
this._changed.emit({
type: 'remove',
oldIndex: startIndex,
newIndex: -1,
oldValues,
newValues: []
});
return this.length;
}
private _array: Array<T> = [];
private _isDisposed = false;
private _itemCmp: (first: T, second: T) => boolean;
private _changed = new Signal<this, IObservableList.IChangedArgs<T>>(this);
}
/**
* The namespace for `ObservableList` class statics.
*/
export namespace ObservableList {
/**
* The options used to initialize an observable map.
*/
export interface IOptions<T> {
/**
* An optional initial set of values.
*/
values?: IterableOrArrayLike<T>;
/**
* The item comparison function for change detection on `set`.
*
* If not given, strict `===` equality will be used.
*/
itemCmp?: (first: T, second: T) => boolean;
}
}
/**
* The namespace for module private data.
*/
namespace Private {
/**
* The default strict equality item cmp.
*/
export function itemCmp(first: any, second: any): boolean {
return first === second;
}
}