Merge pull request #538 from flowreaction/flowreaction/issue534

fix(issue 534): replace reduce + spread operator with performant variant

src/_internals/utils.ts

@@ -27,23 +27,24 @@ export type InferErrTypes<R> = R extends Result<unknown, infer E> ? E : never
 export type InferAsyncOkTypes<R> = R extends ResultAsync<infer T, unknown> ? T : never
 export type InferAsyncErrTypes<R> = R extends ResultAsync<unknown, infer E> ? E : never
 
-const appendValueToEndOfList = <T>(value: T) => (list: T[]): T[] => [...list, value]
-
 /**
  * Short circuits on the FIRST Err value that we find
  */
 export const combineResultList = <T, E>(
   resultList: readonly Result<T, E>[],
-): Result<readonly T[], E> =>
-  resultList.reduce(
-    (acc, result) =>
-      acc.isOk()
-        ? result.isErr()
-          ? err(result.error)
-          : acc.map(appendValueToEndOfList(result.value))
-        : acc,
-    ok([]) as Result<T[], E>,
-  )
+): Result<readonly T[], E> => {
+  let acc = ok([]) as Result<T[], E>
+
+  for (const result of resultList) {
+    if (result.isErr()) {
+      acc = err(result.error)
+      break
+    } else {
+      acc.map((list) => list.push(result.value))
+    }
+  }
+  return acc
+}
 
 /* This is the typesafe version of Promise.all
  *
@@ -62,18 +63,21 @@ export const combineResultAsyncList = <T, E>(
  */
 export const combineResultListWithAllErrors = <T, E>(
   resultList: readonly Result<T, E>[],
-): Result<readonly T[], E[]> =>
-  resultList.reduce(
-    (acc, result) =>
-      result.isErr()
-        ? acc.isErr()
-          ? err([...acc.error, result.error])
-          : err([result.error])
-        : acc.isErr()
-        ? acc
-        : ok([...acc.value, result.value]),
-    ok([]) as Result<T[], E[]>,
-  )
+): Result<readonly T[], E[]> => {
+  let acc = ok([]) as Result<T[], E[]>
+
+  for (const result of resultList) {
+    if (result.isErr() && acc.isErr()) {
+      acc.error.push(result.error)
+    } else if (result.isErr() && acc.isOk()) {
+      acc = err([result.error])
+    } else if (result.isOk() && acc.isOk()) {
+      acc.value.push(result.value)
+    }
+    // do nothing when result.isOk() && acc.isErr()
+  }
+  return acc
+}
 
 export const combineResultAsyncListWithAllErrors = <T, E>(
   asyncResultList: readonly ResultAsync<T, E>[],