Cascade Dropdowns

Pick a province, then a district, then a subdistrict — the postal code appears once all three are selected:

Loading address data…

The enumeration API

Besides text search, the library ships a set of functions for building cascading (province → district → subdistrict) dropdowns without typing anything:

import { listProvinces, listAmphures, listTambons } from 'thaizip'

listProvinces(index)            // 77 provinces, sorted by Thai name
listAmphures(index, provinceId)
listTambons(index, amphureId)   // each with its zipCode

• listProvinces(index) returns all 77 provinces, sorted by their Thai name
• listAmphures(index, provinceId) returns every district in that province
• listTambons(index, amphureId) returns every subdistrict in that district, each with its zipCode

Why it’s fast

All three functions read from groupings (byProvince / byAmphure) that are pre-built when the index is created, not from scanning all 7,385 records on every call. That makes them cheap to call on every selection change without hurting performance.

Unknown ids

Calling listAmphures or listTambons with an id that doesn’t exist — a 0 placeholder before anything is selected, or stale state left over from a previous selection — always returns an empty array [], never throws. That makes it safe to reset child selections when a parent selection changes, as the demo above does (picking a new province resets amphureId/tambonId back to 0).