feat: add form and page platform

src/presentation/forms/form-contracts.ts

@@ -0,0 +1,69 @@
+import type { ApiFailure } from "../../contracts/errors.js";
+
+export type FormValues = Readonly<Record<string, unknown>>;
+export type FieldName<Values extends FormValues> = Extract<keyof Values, string>;
+export type FieldErrors<Values extends FormValues> = Readonly<
+  Partial<Record<FieldName<Values>, string>>
+>;
+
+export type FormResult<Value> =
+  | Readonly<{ ok: true; value: Value }>
+  | Readonly<{ ok: false; error: ApiFailure }>;
+
+export type FormResultState =
+  | "idle"
+  | "success"
+  | "validation-error"
+  | "conflict"
+  | "unavailable";
+
+export type MappedValidationFailure<Values extends FormValues> = Readonly<{
+  fieldErrors: FieldErrors<Values>;
+  formErrors: readonly string[];
+}>;
+
+const VALIDATION_COPY = Object.freeze({
+  REQUIRED: "필수 입력값입니다.",
+  too_small: "입력값이 너무 짧습니다.",
+  too_big: "입력값이 너무 깁니다.",
+  invalid_type: "입력 형식을 확인해 주세요.",
+  invalid_format: "입력 형식을 확인해 주세요.",
+  invalid_value: "허용된 값을 선택해 주세요.",
+});
+
+export function validationMessage(code: string): string {
+  return (
+    VALIDATION_COPY[code as keyof typeof VALIDATION_COPY] ??
+    "입력값을 확인해 주세요."
+  );
+}
+
+export function mapValidationFailureToFields<Values extends FormValues>(
+  failure: ApiFailure,
+  allowedFields: readonly FieldName<Values>[],
+): MappedValidationFailure<Values> {
+  if (failure.kind !== "VALIDATION_REJECTED") {
+    return Object.freeze({ fieldErrors: Object.freeze({}), formErrors: [] });
+  }
+  const allowed = new Set<string>(allowedFields);
+  const fieldErrors: Partial<Record<FieldName<Values>, string>> = {};
+  const formErrors: string[] = [];
+  const issues = failure.validationIssues ?? [];
+
+  if (issues.length === 0) {
+    formErrors.push("입력값을 다시 확인해 주세요.");
+  }
+  for (const issue of issues) {
+    const field = issue.path.split(".").at(0) ?? "";
+    if (allowed.has(field)) {
+      const name = field as FieldName<Values>;
+      fieldErrors[name] ??= validationMessage(issue.code);
+    } else {
+      formErrors.push("서버가 확인하지 못한 입력 항목이 있습니다.");
+    }
+  }
+  return Object.freeze({
+    fieldErrors: Object.freeze(fieldErrors),
+    formErrors: Object.freeze([...new Set(formErrors)]),
+  });
+}