feat(medusa): Allow to query product types by discount condition id (#2359)

packages/medusa/src/utils/index.ts

@@ -4,6 +4,7 @@ export * from "./validate-id"
 export * from "./generate-entity-id"
 export * from "./remove-undefined-properties"
 export * from "./is-defined"
+export * from "./is-string"
 export * from "./calculate-price-tax-amount"
 export * from "./csv-cell-content-formatter"
 export * from "./exception-formatter"

packages/medusa/src/utils/is-string.ts

@@ -0,0 +1,3 @@
+export function isString(val: any): val is string {
+  return val != null && typeof val === "string"
+}