Add first version of sending code

Author: winsmith

telemetrydeck.js

@@ -0,0 +1,69 @@
+const transformPayload = (payload) =>
+  Object.entries(payload).map((entry) => entry.join(':'));
+
+const assertOption = (options, key) => {
+  if (!options[key]) {
+    throw Error(`TelemetryDeck: options.${key} is not set`);
+  }
+};
+
+export default async function sendTelemetry(options, payload) {
+  options = {
+    host: 'https://nom.telemetrydeck.com',
+    appID: null,
+    userIdentifier: null,
+    ...options,
+  };
+
+  payload = {
+    url: location.href,
+    useragent: navigator.userAgent,
+    locale: navigator.language,
+    platform: navigator.userAgentData,
+    vendor: navigator.vendor,
+    ...payload,
+  };
+
+  assertOption(options, 'appID');
+  assertOption(options, 'userIdentifier');
+
+  let { appID, userIdentifier } = options;
+
+  userIdentifier = await sha256(userIdentifier);
+
+  return fetch(`${options.host}/api/v1/apps/app/signals/multiple/`, {
+    method: 'POST',
+    mode: 'cors',
+    headers: {
+      'Content-Type': 'application/json',
+    },
+    body: JSON.stringify([
+      {
+        appID: appID,
+        clientUser: userIdentifier,
+        sessionID: userIdentifier,
+        telemetryClientVersion: '0.1.0',
+        type: 'pageview',
+        payload: transformPayload(payload),
+      },
+    ]),
+  });
+}
+
+// https://stackoverflow.com/a/48161723/54547
+async function sha256(message) {
+  // encode as UTF-8
+  const msgBuffer = new TextEncoder().encode(message);
+
+  // hash the message
+  const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);
+
+  // convert ArrayBuffer to Array
+  const hashArray = Array.from(new Uint8Array(hashBuffer));
+
+  // convert bytes to hex string
+  const hashHex = hashArray
+    .map((b) => b.toString(16).padStart(2, '0'))
+    .join('');
+  return hashHex;
+}