diff --git a/app/utils/async-filter.js b/app/utils/async-filter.js
new file mode 100644
index 0000000..a6a4e09
--- /dev/null
+++ b/app/utils/async-filter.js
@@ -0,0 +1,14 @@
+// @flow
+
+export const asyncFilter = async (array: any[], fn: any => Promise<boolean>): Promise<any[]> => {
+  const result = [];
+
+  /* eslint-disable no-restricted-syntax */
+  /* eslint-disable no-await-in-loop */
+
+  for (const cur of array) {
+    if (await fn(cur)) result.push(cur);
+  }
+
+  return result;
+};
diff --git a/app/utils/async-map.js b/app/utils/async-map.js
new file mode 100644
index 0000000..3de96dd
--- /dev/null
+++ b/app/utils/async-map.js
@@ -0,0 +1,14 @@
+// @flow
+
+export const asyncMap = async (array: any[], fn: any => Promise<any>): Promise<any[]> => {
+  const result = [];
+
+  /* eslint-disable no-restricted-syntax */
+  /* eslint-disable no-await-in-loop */
+
+  for (const cur of array) {
+    result.push(await fn(cur));
+  }
+
+  return result;
+};
diff --git a/app/utils/is-hex.js b/app/utils/is-hex.js
new file mode 100644
index 0000000..a2ba994
--- /dev/null
+++ b/app/utils/is-hex.js
@@ -0,0 +1,8 @@
+// @flow
+const HEX_REGEX = /([0-9]|[a-f])/gim;
+
+export const isHex = (input: ?string) => {
+  if (!input) return false;
+
+  return (input.match(HEX_REGEX) || []).length === input.length;
+};