Match on values, not keys, duh

app/src/lib/enum.ts

@@ -1,3 +1,7 @@
+type StringEnum<T extends string> = {
+  [key: string]: T
+}
+
 /**
  * Parse a string into the given (string) enum type. Returns undefined if the
  * enum type provided did not match any of the keys in the enum.
@@ -6,13 +10,16 @@
  * one-liner. I measured it and this is 200x faster and doesn't allocate any
  * unnecessary arrays.
  */
-export function parseEnumValue<T>(
-  enumObj: Record<string, T>,
-  key: string
+export function parseEnumValue<T extends string>(
+  enumObj: StringEnum<T>,
+  value: string
 ): T | undefined {
-  for (const k in enumObj) {
-    if (k === key && Object.prototype.hasOwnProperty.call(enumObj, k)) {
-      return enumObj[k]
+  for (const key in enumObj) {
+    if (
+      Object.prototype.hasOwnProperty.call(enumObj, key) &&
+      enumObj[key] === value
+    ) {
+      return enumObj[key]
     }
   }
   return undefined