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startOfQuarterForDate

startOfQuarterForDate(value: string): string
import { startOfQuarterForDate } from "@northguild/gmt/plain/calculate";

Return the first day of the quarter for a given ISO date.

  • Returns the first day (month and day set to 1) of the quarter containing the input date.
  • Q1 returns “01-01”, Q2 returns “04-01”, Q3 returns “07-01”, Q4 returns “10-01”.
  • Validates input using isValidDate.
Parameter Type Description
value string ISO PlainDate string

ISO PlainDate string for the first day of the quarter, or “” on invalid input

startOfQuarterForDate("2024-03-15") // "2024-01-01"
startOfQuarterForDate("2024-06-15") // "2024-04-01"
startOfQuarterForDate("2024-09-15") // "2024-07-01"
startOfQuarterForDate("2024-12-15") // "2024-10-01"
startOfQuarterForDate("invalid") // ""

plain/calculate/startOfQuarterForDate.ts