Pluscode npm package plus a utility function to test if a string may be a pluscode

src/lib/check-pluscode.test.ts

@@ -0,0 +1,38 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import maybePlusCode from './check-pluscodes';
+
+describe('The maybePlusCode method', () => {
+  it('detects a valid short pluscode without qualifier', () => {
+    const code = '9G8F+6W';
+    expect(maybePlusCode(code)).toEqual({ code, isShort: true });
+  });
+  it('detects a valid short pluscode with qualifier', () => {
+    const code = '948G+V4 Oviedo';
+    expect(maybePlusCode(code)).toEqual({
+      code: '948G+V4',
+      qualifier: 'Oviedo',
+      isShort: true,
+    });
+  });
+  it('detects a valid long pluscode with 10 digits', () => {
+    const code = '9FFW84J9+XG';
+    expect(maybePlusCode(code)).toEqual({
+      code,
+      isShort: false,
+    });
+  });
+  it('detects a valid long pluscode with 8 digits', () => {
+    const code = '9FFW84J9+';
+    expect(maybePlusCode(code)).toEqual({
+      code,
+      isShort: false,
+    });
+  });
+  it('detects a valid long pluscode with 4 digits', () => {
+    const code = '9FFW0000+';
+    expect(maybePlusCode(code)).toEqual({
+      code,
+      isShort: false,
+    });
+  });
+});

src/lib/check-pluscodes.ts

@@ -0,0 +1,16 @@
+const maybePlusRegexp =
+  /^([23456789CFGHJMPQRVWX]+0*\+[23456789CFGHJMPQRVWX]*)(\s+(.*))?$/;
+
+const maybePlusCode = (code: string) => {
+  const matches = code.match(maybePlusRegexp);
+  if (!matches) {
+    return false;
+  }
+  return {
+    code: matches[1],
+    isShort: matches[1].length < 9,
+    qualifier: matches[3] || undefined,
+  };
+};
+
+export default maybePlusCode;