From 372961d6b17f38305b156403ce9e2f1bcdea671e Mon Sep 17 00:00:00 2001
From: Erik Brinkman <erik.brinkman@gmail.com>
Date: Wed, 31 Mar 2021 22:19:49 -0400
Subject: [PATCH] improve JSONSchemaType errors

typescript seems to report errors with the last member of a valid union
first, so this rearranges the type so the simple union types come first,
and the type that represents the meaty types comes last. This should
help make errors like the one in #1521 more clear.
---
 lib/types/json-schema.ts | 47 ++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 23 deletions(-)

diff --git a/lib/types/json-schema.ts b/lib/types/json-schema.ts
index be68547ff..20fa4b7f8 100644
--- a/lib/types/json-schema.ts
+++ b/lib/types/json-schema.ts
@@ -24,6 +24,30 @@ interface StringKeywords {
 }
 
 export type JSONSchemaType<T, _partial extends boolean = false> = (
+  | // these two unions allow arbitrary unions of types
+  {
+      anyOf: readonly JSONSchemaType<T, _partial>[]
+    }
+  | {
+      oneOf: readonly JSONSchemaType<T, _partial>[]
+    }
+  // this union allows for { type: (primitive)[] } style schemas
+  | ({
+      type: (T extends number
+        ? JSONType<"number" | "integer", _partial>
+        : T extends string
+        ? JSONType<"string", _partial>
+        : T extends boolean
+        ? JSONType<"boolean", _partial>
+        : never)[]
+    } & (T extends number
+      ? NumberKeywords
+      : T extends string
+      ? StringKeywords
+      : T extends boolean
+      ? unknown
+      : never))
+  // this covers "normal" types; it's last so typescript looks to it first for errors
   | ((T extends number
       ? {
           type: JSONType<"number" | "integer", _partial>
@@ -91,29 +115,6 @@ export type JSONSchemaType<T, _partial extends boolean = false> = (
       else?: PartialSchema<T>
       not?: PartialSchema<T>
     })
-  // these two unions allow arbitrary unions of types
-  | {
-      anyOf: readonly JSONSchemaType<T, _partial>[]
-    }
-  | {
-      oneOf: readonly JSONSchemaType<T, _partial>[]
-    }
-  // this union allows for { type: (primitive)[] } style schemas
-  | ({
-      type: (T extends number
-        ? JSONType<"number" | "integer", _partial>
-        : T extends string
-        ? JSONType<"string", _partial>
-        : T extends boolean
-        ? JSONType<"boolean", _partial>
-        : never)[]
-    } & (T extends number
-      ? NumberKeywords
-      : T extends string
-      ? StringKeywords
-      : T extends boolean
-      ? unknown
-      : never))
 ) & {
   [keyword: string]: any
   $id?: string