Move MaybeBigNumber functions into helper

1 files changed, 25 insertions, 0 deletions

diff --git a/packages/instant/src/util/maybe_big_number.ts b/packages/instant/src/util/maybe_big_number.ts
new file mode 100644
index 000000000..113ba552f
--- /dev/null
+++ b/packages/instant/src/util/maybe_big_number.ts
@@ -0,0 +1,25 @@
+import { BigNumber } from '@0x/utils';
+import * as _ from 'lodash';
+
+import { MaybeBigNumber } from '../types';
+
+export const maybeBigNumberUtil = {
+    // converts a string to a MaybeBigNumber
+    // if string is a NaN, considered undefined
+    stringToMaybeBigNumber: (stringValue: string): MaybeBigNumber => {
+        let validBigNumber: BigNumber;
+        try {
+            validBigNumber = new BigNumber(stringValue);
+        } catch {
+            return undefined;
+        }
+
+        return validBigNumber.isNaN() ? undefined : validBigNumber;
+    },
+    areMaybeBigNumbersEqual: (val1: MaybeBigNumber, val2: MaybeBigNumber): boolean => {
+        if (!_.isUndefined(val1) && !_.isUndefined(val2)) {
+            return val1.equals(val2);
+        }
+        return _.isUndefined(val1) && _.isUndefined(val2);
+    },
+};