/** Per-bucket English defaults, overridable the same "no i18n, but
*  overridable via an options object" way `<lr-date-picker>`/
*  `<lr-source-list>`'s `label-plural` already establish. */
export interface RecencyLabels{today?:string;yesterday?:string;previousWeek?:string;older?:string;}export interface GroupByRecencyOptions<T>{
/** Extracts the timestamp to bucket `item` by. Defaults to assuming `item`
*  itself *is* a `Date` — the simplest possible default for the common
*  case of grouping a plain array of dates. A returned `number` is treated
*  as a standard JS epoch-milliseconds value (`Date.prototype.getTime()`'s
*  own unit) — not a microsecond-epoch `time` type some backends use; a
*  caller bridging from such data converts in its own `getTimestamp`
*  callback. */
getTimestamp?:(item:T)=>Date|number|string;
/** The "current" instant bucket boundaries are computed relative to.
*  Defaults to `new Date()`. Overridable for deterministic tests (and for
*  a caller that wants to bucket relative to something other than the
*  actual current instant, e.g. a fixed "as of" report time). */
now?:Date;
/** Overrides for one or more of the four bucket labels. Any label left
*  unset keeps its English default. */
labels?:RecencyLabels;}export interface RecencyBucket<T>{label:string;items:T[];}
/**
* Buckets `items` into Today / Yesterday / Previous 7 Days / Older, using
* calendar-day boundaries in the local timezone — "yesterday" means the
* previous calendar date, not "24-48 hours ago". Mirrors the bucketing a
* chat sidebar's conversation-history list commonly groups by (this
* library's own `<lr-conversation-item>` is the intended consumer, though
* this function is deliberately DOM/component-free — plain data in, plain
* data out).
*
* Only buckets that end up with at least one item are included in the
* returned array, in Today/Yesterday/Previous-7-Days/Older order; each
* bucket's items keep their original relative order from `items` (never
* re-sorted). Two edge cases with no dedicated bucket of their own: a
* timestamp dated in the future relative to `now` lands in `Today` — the
* most-recent bucket available, since there's no "upcoming" bucket to put it
* in instead. A timestamp that fails to parse lands in `Older` instead — it
* carries no "this is recent" signal at all, so the oldest/catch-all bucket
* is the more honest home for it than the newest one.
*/
export declare function groupByRecency<T>(items:T[],options?:GroupByRecencyOptions<T>):RecencyBucket<T>[];