Handle NaNs

web/packages/utils/parse.ts

@@ -0,0 +1,19 @@
+/**
+ * A wrapper over parseInt that deals with its sheNaNigans.
+ *
+ * This function takes as an input a string nominally (though the implementation
+ * is meant to work for arbitrary JavaScript values). It parses it into a base
+ * 10 integer. If the result is NaN, it returns undefined, otherwise it returns
+ * the parsed integer.
+ *
+ * From MDN:
+ *
+ * > To be sure that you are working with numbers, coerce the value to a number
+ * > and use Number.isNaN() to test the result()
+ * >
+ * > https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isNaN
+ */
+export const maybeParseInt = (s: string) => {
+    const n = parseInt(s, 10);
+    return Number.isNaN(n) ? undefined : n;
+};