todo.filter

Imports name this capability’s declared dependencies, which fune builds next to it in your project; each one links to its page.

import { searchText } from "./collections_search_text.ts";  ← from collections.search-text ^1.0.0 · built alongside by fune
import { type TodoFilter } from "./todo_filter_types.ts";
import { type Todo } from "./todo_item.ts";  ← from todo.item ^1.0.0 · built alongside by fune
import { trimSpace } from "./todo_item_validate_draft.ts";
import { normaliseTags } from "./todo_normalise_tags.ts";  ← from todo.normalise-tags ^1.0.0 · built alongside by fune

const VIEWS = ["all", "active", "completed"];

/**
 * The todos a list shows for its view tab, tag and search box, in input order.
 *
 * The tag is normalised the way stored tags are (todo.normalise-tags), so
 * "#Home" finds "home". A tag that normalises to nothing ("#", "  ") matches no
 * todo: a tag filter was asked for, and no todo carries an empty tag. The
 * search is collections.search-text over the title, the notes and the tags
 * joined with spaces, so searching "home" also finds todos tagged home.
 */
export function filterTodos(todos: readonly Todo[], filter: TodoFilter): readonly Todo[] {
  if (!VIEWS.includes(filter.view)) {
    throw new RangeError(`unknown view "${filter.view}": expected all, active or completed`);
  }
  let wanted: string | null = null;
  if (filter.tag !== null && filter.tag !== undefined) {
    const tags = normaliseTags([filter.tag]);
    if (tags.length === 0) return [];
    wanted = tags[0];
  }
  const kept: Todo[] = [];
  for (const todo of todos) {
    if (filter.view === "active" && todo.done) continue;
    if (filter.view === "completed" && !todo.done) continue;
    if (wanted !== null && !todo.tags.includes(wanted)) continue;
    kept.push(todo);
  }
  const query = trimSpace(filter.query);
  if (query === "") return kept;
  const records = kept.map((todo, i) => ({ i, title: todo.title, notes: todo.notes, tags: todo.tags.join(" ") }));
  return searchText(records, ["title", "notes", "tags"], query).map((r) => kept[r.i as number]);
}