formatWhen()function

formatWhen(target: PossibleDate, current?: PossibleDate, options?: UnitFormatOptions, caller: AnyCaller = formatWhen): string

Param	Type
`target`	`PossibleDate`	Date the duration is measured to. required
`current`	`PossibleDate`	Date the duration is measured from (defaults to now).
`options`	`UnitFormatOptions`	Formatting options for the chosen duration unit.
`.one`	`string`	String for one of this thing, e.g. `product` or `item` or `sheep` - Used for `unitDisplay: "long"` formatting. - Defaults to unit reference, e.g. "minute" readonly
`.many`	`string`	String for several of this thing, e.g. `products` or `items` or `sheep` - Used for `unitDisplay: "long"` formatting. - Defaults to `one + "s"` readonly
`.abbr`	`string`	Abbreviation for this thing, e.g. `products` or `items` or `sheep` (defaults to `one` + "s"). - Used for `unitDisplay: "narrow"` formatting. - Defaults to unit reference, e.g. "minute" readonly
`caller`	`AnyCaller`	Function to attribute a thrown error to (defaults to `formatWhen` itself). Defaults to `formatWhen`

Return
`string`	Compact string like `in 10d`, `2h ago`, or `just now`.

Throws
`RequiredError`	If `target` or `current` cannot be converted to a valid date.

Format a compact best-fit description of when a date happens or happened, e.g. in 10d or 2h ago or in 1w or just now

See getBestDurationUnit() for details on how the best-fit unit is chosen.
But: anything under 30 seconds will show just now, which makes more sense in most UIs.

Examples

formatWhen("2099-01-01") // "in 73 years"