tree-explorer.ts

export function* dfs<T>(root: T) {
  const stack: T[] = [root];
  let target: T|undefined;
  
  while (target = stack.shift()) {
    const cb: DFSNext<T> = yield target;
    stack.unshift(...cb?.(target) ?? []);
  }
}

export function* createDFSIterable<T>(root: T, next: DFSNext<T>) {
  const iteratble = dfs(root);
  let value: T|void;
  let done: boolean|undefined;
  while (({value, done} = iteratble.next(next)), !done) yield value;
}
/*
type Item = {
  a: number;
  children?: Item[];
};
const iterable = createDFSIterable<Item>(({a: 3, children: [{a: 4, children: [{a: 5}, {a: 6}]}, {a: 7}, {a: 8}]}), ({children}) => children);
*/

export function* bfs<T>(data: T) {
  const stack: T[] = [data];
  let target: T | undefined;

  while ((target = stack.shift())) {
    const cb: (target: T) => T[] | undefined = yield target;
    if (typeof cb !== "function")
      return;
    const children = cb(target);
    children && stack.push(...children);
  }
}
export const createDfs = <T>(f: (p: T) => T[] | undefined) => function* (data: T) {
  const iterator = dfs(data);
  let target;
  while (!(target = iterator.next(f)).done) yield target.value;
};
export const createBfs = <T>(f: (p: T) => T[] | undefined) => function* (data: T) {
  const iterator = bfs(data);
  let target;
  while (!(target = iterator.next(f)).done) yield target.value;
};