Function: generalizeZip()

generalizeZip(zip): GeneralizeOutcome | null

Generalize a ZIP code to its safe form (§164.514(b)(2)(i)(B)): the initial three digits, or 000 when those three digits name an area with ≤ 20,000 people (the cited restricted list). Fails closed (null) when three leading digits cannot be read.

Parameters

zip

string

The ZIP code (5-digit, ZIP+4, or any form beginning with digits).

Returns

GeneralizeOutcome | null

The { value, residual } outcome - residual: false for 000, true for a kept prefix - or null if fewer than three leading digits are present.

Example

import { generalizeZip } from "@cosyte/deid";

generalizeZip("90210")?.value; // => "902"
generalizeZip("03601")?.value; // => "000"  (036 is a restricted prefix)