zulip/web/src/fold_dict.ts

76 lines
1.8 KiB
TypeScript

/*
Use this class to manage keys where you don't care
about case (i.e. case-insensitive).
Keys for FoldDict should be strings. We "fold" all
casings of "alice" (e.g. "ALICE", "Alice", "ALIce", etc.)
to "alice" as the key.
Examples of case-insensitive data in Zulip are:
- emails
- stream names
- topics
- etc.
*/
type KeyValue<V> = {k: string; v: V};
export class FoldDict<V> {
private _items = new Map<string, KeyValue<V>>();
get size(): number {
return this._items.size;
}
get(key: string): V | undefined {
const mapping = this._items.get(this._munge(key));
if (mapping === undefined) {
return undefined;
}
return mapping.v;
}
set(key: string, value: V): this {
this._items.set(this._munge(key), {k: key, v: value});
return this;
}
has(key: string): boolean {
return this._items.has(this._munge(key));
}
delete(key: string): boolean {
return this._items.delete(this._munge(key));
}
*keys(): IterableIterator<string> {
for (const {k} of this._items.values()) {
yield k;
}
}
*values(): IterableIterator<V> {
for (const {v} of this._items.values()) {
yield v;
}
}
*[Symbol.iterator](): IterableIterator<[string, V]> {
for (const {k, v} of this._items.values()) {
yield [k, v];
}
}
clear(): void {
this._items.clear();
}
// Handle case-folding of keys and the empty string.
private _munge(key: string): string {
if (key === undefined) {
throw new TypeError("Tried to call a FoldDict method with an undefined key.");
}
return key.toString().toLowerCase();
}
}