todo.group-by-due

export function groupByDue(todos: readonly Todo[], today: string): readonly DueGroup[]

/** One section of a todo list grouped by due date. */
export interface DueGroup {
  readonly status: DueStatus;
  /** Overdue, Today, Tomorrow, This week, Later, No date or Done */
  readonly title: string;
  readonly todos: readonly Todo[];
}

import { groupByDue } from "#fune/todo.group-by-due@^1";

import { dayOfWeek } from "./dates_day_of_week.ts";  ← from dates.day-of-week ^1.0.0 · built alongside by fune
import { type DueStatus, dueStatus } from "./todo_due_status.ts";  ← from todo.due-status ^1.0.0 · built alongside by fune
import { type DueGroup } from "./todo_group_by_due_types.ts";
import { type Todo } from "./todo_item.ts";  ← from todo.item ^1.0.0 · built alongside by fune

const SECTIONS: readonly [DueStatus, string][] = [
  ["overdue", "Overdue"],
  ["today", "Today"],
  ["tomorrow", "Tomorrow"],
  ["this-week", "This week"],
  ["later", "Later"],
  ["none", "No date"],
  ["done", "Done"],
];

/**
 * Todos in planner sections, fixed order, empty sections left out. Sections
 * spanning several dates are sorted by due date, stably; the rest keep the
 * caller's order, so a list pre-sorted by priority stays that way.
 */
export function groupByDue(todos: readonly Todo[], today: string): readonly DueGroup[] {
  dayOfWeek(today); // a bad today is an error even for an empty list
  const statuses = todos.map((todo) => dueStatus(todo, today));
  const groups: DueGroup[] = [];
  for (const [status, title] of SECTIONS) {
    const members = todos.filter((_, i) => statuses[i] === status);
    if (members.length === 0) continue;
    if (status === "overdue" || status === "this-week" || status === "later") {
      // Array.prototype.sort is stable, so equal dates keep input order.
      members.sort((a, b) => ((a.due as string) < (b.due as string) ? -1 : (a.due as string) > (b.due as string) ? 1 : 0));
    }
    groups.push({ status, title, todos: members });
  }
  return groups;
}

Install

fune build

With that line in your source, in a TypeScript project (language typescript in fune.project), fune build resolves it and its 3 dependencies, pins them in fune.lock, downloads only the TypeScript package of each, and builds the code above into your project’s .fune/build, one readable file per capability with a header linking back here. Or pin a range in fune.project and build in one step:

fune add todo.group-by-due

The manifest, vectors and README with only the TypeScript implementation. Install it without the registry with fune add ./todo.group-by-due-1.0.0-typescript.fune, or fetch it from a terminal with fune pull todo.group-by-due@1.0.0:typescript.

The whole function, every language, is one file too: todo.group-by-due-1.0.0.fune, 27,566 bytes, sha256 1481e318e0c34459c62eda3eb94aeb9446f0f310526596be41943d6b38f8f888. It installs into a project of any language.

// fune: before todo.group-by-due

// fune: after todo.group-by-due

// fune: replace dates.day-of-week in todo.group-by-due
// fune: replace todo.due-status in todo.group-by-due
// fune: replace todo.item in todo.group-by-due

// fune: step todo.group-by-due after <n|label>

More from the author

| status | title | | --- | --- | | overdue | Overdue | | today | Today | | tomorrow | Tomorrow | | this-week | This week | | later | Later | | none | No date | | done | Done |

- **Overdue, This week and Later are sorted by due date**, earliest first, because they span several dates. The sort is stable: todos with the same due date keep their input order. - **Today, Tomorrow, No date and Done keep the input order**, since every todo in them has the same date (or none). So sort first by whatever you prefer (priority, manual order, title) and the grouping keeps it inside each section and among equal dates. - The titles are English. A localised app maps `status` to its own strings. - "This week" is the rest of the ISO week after tomorrow (see todo.due-status): on Saturday and Sunday there is no This week section. - `today` is checked even for an empty list, and a malformed or impossible date anywhere is an error (dates.add-days's messages).

Files