feat(utils): add helpers

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;
+};

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;
+};

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;
+};