add findByPhoneNumber function so we can query VAN for persons with a…

… specified phone number

src/extensions/action-handlers/ngpvan-action.js

@@ -102,6 +102,28 @@ export const postCanvassResponse = async (contact, organization, bodyInput) => {
   });
 };
 
+// Queries VAN on a specific phone number, returning information on
+// the owner. 
+// NOTE: VAN has a limit of 10 queries per second:
+// https://docs.ngpvan.com/docs/limitations-and-warnings#billing-and-usage
+export async function findByPhoneNumber( phoneNumber, organization ) {
+
+  const url = Van.makeUrl("v4/people/findByPhone", organization);
+
+  return httpRequest(url, {
+    method: "POST",
+    retries: 0, // could we do more?
+    timeout: Van.getNgpVanTimeout(organization),
+    headers: {
+      Authorization: await Van.getAuth(organization),
+      "Content-Type": "application/json"
+    },
+    body: `{ "phoneNumber": "${phoneNumber}" }`,
+    validStatuses: [204],
+    compess: false
+  });
+}
+
 // What happens when a texter saves the answer that triggers the action
 // This is presumably the meat of the action
 export async function processAction({ actionObject, contact, organization }) {