langium
Version:
A language engineering tool for the Language Server Protocol
195 lines • 5.74 kB
JavaScript
/******************************************************************************
* Copyright 2021 TypeFox GmbH
* This program and the accompanying materials are made available under the
* terms of the MIT License, which is available in the project root.
******************************************************************************/
import { EMPTY_STREAM, Reduction, stream } from './stream.js';
/**
* A multimap is a variation of a Map that has potentially multiple values for every key.
*/
export class MultiMap {
constructor(elements) {
this.map = new Map();
if (elements) {
for (const [key, value] of elements) {
this.add(key, value);
}
}
}
/**
* The total number of values in the multimap.
*/
get size() {
return Reduction.sum(stream(this.map.values()).map(a => a.length));
}
/**
* Clear all entries in the multimap.
*/
clear() {
this.map.clear();
}
/**
* Operates differently depending on whether a `value` is given:
* * With a value, this method deletes the specific key / value pair from the multimap.
* * Without a value, all values associated with the given key are deleted.
*
* @returns `true` if a value existed and has been removed, or `false` if the specified
* key / value does not exist.
*/
delete(key, value) {
if (value === undefined) {
return this.map.delete(key);
}
else {
const values = this.map.get(key);
if (values) {
const index = values.indexOf(value);
if (index >= 0) {
if (values.length === 1) {
this.map.delete(key);
}
else {
values.splice(index, 1);
}
return true;
}
}
return false;
}
}
/**
* Returns an array of all values associated with the given key. If no value exists,
* an empty array is returned.
*
* _Note:_ The returned array is assumed not to be modified. Use the `set` method to add a
* value and `delete` to remove a value from the multimap.
*/
get(key) {
return this.map.get(key) ?? [];
}
/**
* Returns a stream of all values associated with the given key. If no value exists,
* {@link EMPTY_STREAM} is returned.
*/
getStream(key) {
const values = this.map.get(key);
return values ? stream(values) : EMPTY_STREAM;
}
/**
* Operates differently depending on whether a `value` is given:
* * With a value, this method returns `true` if the specific key / value pair is present in the multimap.
* * Without a value, this method returns `true` if the given key is present in the multimap.
*/
has(key, value) {
if (value === undefined) {
return this.map.has(key);
}
else {
const values = this.map.get(key);
if (values) {
return values.indexOf(value) >= 0;
}
return false;
}
}
/**
* Add the given key / value pair to the multimap.
*/
add(key, value) {
if (this.map.has(key)) {
this.map.get(key).push(value);
}
else {
this.map.set(key, [value]);
}
return this;
}
/**
* Add the given set of key / value pairs to the multimap.
*/
addAll(key, values) {
if (this.map.has(key)) {
this.map.get(key).push(...values);
}
else {
this.map.set(key, Array.from(values));
}
return this;
}
/**
* Invokes the given callback function for every key / value pair in the multimap.
*/
forEach(callbackfn) {
this.map.forEach((array, key) => array.forEach(value => callbackfn(value, key, this)));
}
/**
* Returns an iterator of key, value pairs for every entry in the map.
*/
[Symbol.iterator]() {
return this.entries().iterator();
}
/**
* Returns a stream of key, value pairs for every entry in the map.
*/
entries() {
return stream(this.map.entries())
.flatMap(([key, array]) => array.map(value => [key, value]));
}
/**
* Returns a stream of keys in the map.
*/
keys() {
return stream(this.map.keys());
}
/**
* Returns a stream of values in the map.
*/
values() {
return stream(this.map.values()).flat();
}
/**
* Returns a stream of key, value set pairs for every key in the map.
*/
entriesGroupedByKey() {
return stream(this.map.entries());
}
}
export class BiMap {
get size() {
return this.map.size;
}
constructor(elements) {
this.map = new Map();
this.inverse = new Map();
if (elements) {
for (const [key, value] of elements) {
this.set(key, value);
}
}
}
clear() {
this.map.clear();
this.inverse.clear();
}
set(key, value) {
this.map.set(key, value);
this.inverse.set(value, key);
return this;
}
get(key) {
return this.map.get(key);
}
getKey(value) {
return this.inverse.get(value);
}
delete(key) {
const value = this.map.get(key);
if (value !== undefined) {
this.map.delete(key);
this.inverse.delete(value);
return true;
}
return false;
}
}
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