refactor: flatten

library/src/error/flatten/flatten.ts

@@ -26,7 +26,9 @@ import type {
   BaseSchema,
   BaseSchemaAsync,
   Input,
+  Issue,
   Issues,
+  PathItem,
 } from '../../types/index.ts';
 import type { ValiError } from '../ValiError/index.ts';
 
@@ -49,7 +51,7 @@ type ObjectPath<TEntries extends ObjectEntries | ObjectEntriesAsync> = {
 /**
  * Tuple key type.
  */
-type TupleKey<T extends any[]> = Exclude<keyof T, keyof any[]>;
+type TupleKey<T extends unknown[]> = Exclude<keyof T, keyof unknown[]>;
 
 /**
  * Tuple path type.
@@ -118,7 +120,7 @@ type NestedPath<TSchema extends BaseSchema | BaseSchemaAsync> =
 /**
  * Flat errors type.
  */
-export type FlatErrors<TSchema extends BaseSchema | BaseSchemaAsync = any> = {
+export type FlatErrors<TSchema extends BaseSchema | BaseSchemaAsync> = {
   root?: [string, ...string[]];
   nested: Partial<Record<NestedPath<TSchema>, [string, ...string[]]>>;
 };
@@ -130,7 +132,7 @@ export type FlatErrors<TSchema extends BaseSchema | BaseSchemaAsync = any> = {
  *
  * @returns Flat errors.
  */
-export function flatten<TSchema extends BaseSchema | BaseSchemaAsync = any>(
+export function flatten<TSchema extends BaseSchema | BaseSchemaAsync>(
   error: ValiError
 ): FlatErrors<TSchema>;
 
@@ -141,39 +143,61 @@ export function flatten<TSchema extends BaseSchema | BaseSchemaAsync = any>(
  *
  * @returns Flat errors.
  */
-export function flatten<TSchema extends BaseSchema | BaseSchemaAsync = any>(
+export function flatten<TSchema extends BaseSchema | BaseSchemaAsync>(
   issues: Issues
 ): FlatErrors<TSchema>;
 
-export function flatten<TSchema extends BaseSchema | BaseSchemaAsync = any>(
+export function flatten<TSchema extends BaseSchema | BaseSchemaAsync>(
   arg1: ValiError | Issues
 ): FlatErrors<TSchema> {
-  return (Array.isArray(arg1) ? arg1 : arg1.issues).reduce<FlatErrors<TSchema>>(
-    (flatErrors, issue) => {
-      if (issue.path) {
-        if (
-          issue.path.every(
-            ({ key }) => typeof key === 'string' || typeof key === 'number'
-          )
-        ) {
-          const path = issue.path.map(({ key }) => key).join('.') as NestedPath<
-            Input<TSchema>
-          >;
-          if (flatErrors.nested[path]) {
-            flatErrors.nested[path]!.push(issue.message);
-          } else {
-            flatErrors.nested[path] = [issue.message];
-          }
-        }
-      } else {
-        if (flatErrors.root) {
-          flatErrors.root.push(issue.message);
-        } else {
-          flatErrors.root = [issue.message];
-        }
-      }
-      return flatErrors;
-    },
-    { nested: {} }
+  const issues = Array.isArray(arg1) ? arg1 : arg1.issues;
+  return issues.reduce<FlatErrors<TSchema>>(processIssue, { nested: {} });
+}
+
+function processIssue<TSchema extends BaseSchema | BaseSchemaAsync>(
+  flatErrors: FlatErrors<TSchema>,
+  issue: Issue
+): FlatErrors<TSchema> {
+  if (issue.path && isPathValid(issue.path)) {
+    const path = formatPath(issue.path);
+    updateNestedErrors(flatErrors, path, issue.message);
+  } else {
+    updateRootErrors(flatErrors, issue.message);
+  }
+  return flatErrors;
+}
+
+function isPathValid(path: PathItem[]): boolean {
+  return path.every(
+    ({ key }) => typeof key === 'string' || typeof key === 'number'
   );
 }
+
+function formatPath<TSchema extends BaseSchema | BaseSchemaAsync>(
+  path: PathItem[]
+): NestedPath<TSchema> {
+  return path.map(({ key }) => key).join('.') as NestedPath<Input<TSchema>>;
+}
+
+function updateNestedErrors<TSchema extends BaseSchema | BaseSchemaAsync>(
+  flatErrors: FlatErrors<TSchema>,
+  path: keyof Record<NestedPath<TSchema>, [string, ...string[]]>,
+  message: string
+): void {
+  if (flatErrors.nested[path]) {
+    flatErrors.nested[path]!.push(message);
+  } else {
+    flatErrors.nested[path] = [message];
+  }
+}
+
+function updateRootErrors<TSchema extends BaseSchema | BaseSchemaAsync>(
+  flatErrors: FlatErrors<TSchema>,
+  message: string
+): void {
+  if (flatErrors.root) {
+    flatErrors.root.push(message);
+  } else {
+    flatErrors.root = [message];
+  }
+}