diff --git a/src/lib/utils/host.js b/src/lib/utils/host.js
deleted file mode 100644
index 675881613..000000000
--- a/src/lib/utils/host.js
+++ /dev/null
@@ -1,45 +0,0 @@
-const isDocker = (() => {
-    let isDocker;
-
-    const hostname = require('os').hostname();
-    const pattern = new RegExp(
-        '[0-9]+\:[a-z_-]+\:\/docker\/' + hostname + '[0-9a-z]+', 'i'
-    );
-
-    try {
-        isDocker = require('child_process')
-            .execSync(
-                'cat /proc/self/cgroup',
-                {stdio: ['ignore', 'pipe', 'ignore']}
-            )
-            .toString().match(pattern) !== null;
-    } catch (e) {
-        isDocker = false;
-    }
-
-    return isDocker;
-})();
-
-const defaultHost = isDocker ? '0.0.0.0' : 'localhost';
-
-// when we're runing in Docker, we can expect (generally, in a development
-// scenario) that the user would like to connect to the service in the
-// container via the **host's** loopback address, so this helper can be used to
-// swap 0.0.0.0 for localhost in code/messages that pertain to client-side
-function canonicalHost(host) {
-    return isDocker && host === '0.0.0.0' ? 'localhost' : host;
-}
-
-function dockerHostSwap(host) {
-    return (isDocker && (host === 'localhost' || host === '127.0.0.1')) ? defaultHost : host;
-}
-
-const defaultCorsHost = canonicalHost(defaultHost);
-
-module.exports = {
-    canonicalHost,
-    defaultCorsHost,
-    defaultHost,
-    dockerHostSwap,
-    isDocker
-};
diff --git a/src/lib/utils/host.ts b/src/lib/utils/host.ts
new file mode 100644
index 000000000..3e1a1c379
--- /dev/null
+++ b/src/lib/utils/host.ts
@@ -0,0 +1,45 @@
+const isDocker = (() => {
+  let isDockerProcess;
+
+  const hostname = require("os").hostname();
+  const pattern = new RegExp(
+    "[0-9]+\:[a-z_-]+\:\/docker\/" + hostname + "[0-9a-z]+", "i",
+  );
+
+  try {
+    isDockerProcess = require("child_process")
+    .execSync(
+      "cat /proc/self/cgroup",
+      {stdio: ["ignore", "pipe", "ignore"]},
+    )
+    .toString().match(pattern) !== null;
+  } catch (e) {
+    isDockerProcess = false;
+  }
+
+  return isDockerProcess;
+})();
+
+const defaultHost = isDocker ? "0.0.0.0" : "localhost";
+
+// when we"re runing in Docker, we can expect (generally, in a development
+// scenario) that the user would like to connect to the service in the
+// container via the **host"s** loopback address, so this helper can be used to
+// swap 0.0.0.0 for localhost in code/messages that pertain to client-side
+function canonicalHost(host: string): string {
+  return isDocker && host === "0.0.0.0" ? "localhost" : host;
+}
+
+function dockerHostSwap(host: string): string {
+  return (isDocker && (host === "localhost" || host === "127.0.0.1")) ? defaultHost : host;
+}
+
+const defaultCorsHost = canonicalHost(defaultHost);
+
+export {
+  canonicalHost,
+  defaultCorsHost,
+  defaultHost,
+  dockerHostSwap,
+  isDocker,
+};