feat(next): implement file validation

next/src/errors/index.ts

@@ -7,24 +7,44 @@ export type SchemaValidationErrorType =
   /**
    * Core validation keywords
    */
-  | 'type' | 'required' | 'valid' | 'const' | 'enum'
+  | 'type'
+  | 'required'
+  | 'valid'
+  | 'const'
+  | 'enum'
   /**
    * Schema composition keywords (allOf, anyOf, oneOf, not)
    * These keywords apply subschemas in a logical manner according to JSON Schema spec
    */
-  | 'anyOf' | 'oneOf' | 'not'
+  | 'anyOf'
+  | 'oneOf'
+  | 'not'
   /**
    * String validation keywords
    */
-  | 'format' | 'minLength' | 'maxLength' | 'pattern'
+  | 'format'
+  | 'minLength'
+  | 'maxLength'
+  | 'pattern'
   /**
    * Number validation keywords
    */
-  | 'multipleOf' | 'maximum' | 'exclusiveMaximum' | 'minimum' | 'exclusiveMinimum'
+  | 'multipleOf'
+  | 'maximum'
+  | 'exclusiveMaximum'
+  | 'minimum'
+  | 'exclusiveMinimum'
   /**
    * Date validation keywords
    */
-  | 'minDate' | 'maxDate'
+  | 'minDate'
+  | 'maxDate'
+  /**
+   * File validation keywords
+   */
+  | 'fileStructure'
+  | 'maxFileSize'
+  | 'accept'
   /**
    * Array validation keywords
    */

next/src/errors/messages.ts

@@ -1,6 +1,7 @@
 import type { SchemaValidationErrorType } from '.'
 import type { JsfSchemaType, NonBooleanJsfSchema, SchemaValue } from '../types'
 import { randexp } from 'randexp'
+import { convertKBToMB } from '../utils'
 import { DATE_FORMAT } from '../validation/custom/date'
 
 export function getErrorMessage(
@@ -9,6 +10,7 @@ export function getErrorMessage(
   validation: SchemaValidationErrorType,
   customErrorMessage?: string,
 ): string {
+  const presentation = schema['x-jsf-presentation']
   switch (validation) {
     // Core validation
     case 'type':
@@ -60,11 +62,24 @@ export function getErrorMessage(
       return `Must be greater or equal to ${schema.minimum}`
     case 'exclusiveMinimum':
       return `Must be greater than ${schema.exclusiveMinimum}`
-      // Date validation
+    // Date validation
     case 'minDate':
-      return `The date must be ${schema['x-jsf-presentation']?.minDate} or after.`
+      return `The date must be ${presentation?.minDate} or after.`
     case 'maxDate':
-      return `The date must be ${schema['x-jsf-presentation']?.maxDate} or before.`
+      return `The date must be ${presentation?.maxDate} or before.`
+    // File validation
+    case 'fileStructure':
+      return 'Not a valid file.'
+    case 'maxFileSize': {
+      const limitKB = presentation?.maxFileSize
+      const limitMB = typeof limitKB === 'number' ? convertKBToMB(limitKB) : undefined
+      return `File size too large.${limitMB ? ` The limit is ${limitMB} MB.` : ''}`
+    }
+    case 'accept': {
+      const formats = presentation?.accept
+      return `Unsupported file format.${formats ? ` The acceptable formats are ${formats}.` : ''}`
+    }
+    // Arrays
     case 'minItems':
       throw new Error('Array support is not implemented yet')
     case 'maxItems':

next/src/utils.ts

@@ -42,4 +42,12 @@ export function getField(fields: Field[], name: string, ...subNames: string[]) {
     return getField(field.fields, subNames[0], ...subNames.slice(1))
   }
   return field
-};
+}
+
+// Helper function to convert KB to MB
+export function convertKBToMB(kb: number): number {
+  if (kb === 0)
+    return 0
+  const mb = kb / 1024 // KB to MB
+  return Number.parseFloat(mb.toFixed(2)) // Keep 2 decimal places
+}

next/src/validation/file.ts

@@ -0,0 +1,99 @@
+import type { ValidationError, ValidationErrorPath } from '../errors'
+import type { NonBooleanJsfSchema, SchemaValue } from '../types'
+import { isObjectValue } from './util'
+
+// Represents a file-like object, either a browser native File or a plain object.
+// Both must have name (string) and size (number) properties.
+export type FileLike = (File & { name: string, size: number }) | { name: string, size: number }
+
+/**
+ * Validates file-specific constraints (maxFileSize, accept).
+ *
+ * The value is expected to be `null`, `undefined`, or an array of `FileLike` objects.
+ * Each `FileLike` object must have `name` (string) and `size` (number) properties.
+ *
+ * @param value - The value to validate.
+ * @param schema - The schema object, potentially containing 'x-jsf-presentation' with
+ *                 'maxFileSize' (in KB) and/or 'accept' (comma-separated string).
+ * @param path - The path to the current field in the validation context.
+ * @returns An array of validation errors, empty if validation passes.
+ */
+export function validateFile(
+  value: SchemaValue,
+  schema: NonBooleanJsfSchema,
+  path: ValidationErrorPath = [],
+): ValidationError[] {
+  // Early exit conditions
+  // 1. Check if schema indicates a potential file input
+  const presentation = schema['x-jsf-presentation']
+  const isExplicitFileInput = presentation?.inputType === 'file'
+  const hasFileKeywords
+    = typeof presentation?.maxFileSize === 'number' || typeof presentation?.accept === 'string'
+  const isPotentialFileInput = isExplicitFileInput || hasFileKeywords
+
+  if (!isPotentialFileInput) {
+    return [] // Not a file input schema, nothing to validate here.
+  }
+
+  // 2. Check if the value is an array. Non-arrays (like null, object, string) are handled by validateType.
+  if (!Array.isArray(value)) {
+    return [] // File validation only applies to arrays.
+  }
+
+  // Actual file validation logic
+  // If value is an empty array, no further file validation needed.
+  if (value.length === 0) {
+    return []
+  }
+
+  // 2. Check structure of array items: Each item must be a FileLike object.
+  const isStructureValid = value.every(
+    file => isObjectValue(file) && typeof file.name === 'string' && typeof file.size === 'number',
+  )
+
+  if (!isStructureValid) {
+    return [{ path, validation: 'fileStructure' }]
+  }
+
+  // Now we know value is a valid FileLike[] with at least one item.
+  const files = value as FileLike[]
+
+  // 3. Validate maxFileSize (presentation.maxFileSize is expected in KB)
+  if (typeof presentation?.maxFileSize === 'number') {
+    const maxSizeInBytes = presentation.maxFileSize * 1024 // Convert KB from schema to Bytes
+    // Check if *any* file exceeds the limit.
+    const isAnyFileTooLarge = files.some(file => file.size > maxSizeInBytes)
+
+    if (isAnyFileTooLarge) {
+      return [{ path, validation: 'maxFileSize' }]
+    }
+  }
+
+  // 4. Validate accepted file formats (presentation.accept is comma-separated string)
+  if (typeof presentation?.accept === 'string' && presentation.accept.trim() !== '') {
+    const acceptedFormats = presentation.accept
+      .toLowerCase()
+      .split(',')
+      .map((f: string) => f.trim())
+      .filter((f: string) => f)
+      // Normalize formats (handle leading dots)
+      .map((f: string) => (f.startsWith('.') ? f : `.${f}`))
+
+    if (acceptedFormats.length > 0) {
+      // Check if *at least one* file has an accepted format.
+      const isAnyFileFormatAccepted = files.some((file) => {
+        const nameLower = file.name.toLowerCase()
+        const extension = nameLower.includes('.') ? `.${nameLower.split('.').pop()}` : ''
+        return extension !== '' && acceptedFormats.includes(extension)
+      })
+
+      // Fail only if *none* of the files have an accepted format.
+      if (!isAnyFileFormatAccepted) {
+        return [{ path, validation: 'accept' }]
+      }
+    }
+  }
+
+  // If all checks passed
+  return []
+}

next/src/validation/schema.ts

@@ -6,6 +6,7 @@ import { validateCondition } from './conditions'
 import { validateConst } from './const'
 import { validateDate } from './custom/date'
 import { validateEnum } from './enum'
+import { validateFile } from './file'
 import { validateJsonLogic } from './json-logic'
 import { validateNumber } from './number'
 import { validateObject } from './object'
@@ -75,29 +76,37 @@ function validateType(
   const valueType = value === null ? 'null' : Array.isArray(value) ? 'array' : typeof value
 
   if (Array.isArray(schemaType)) {
+    // Handle cases where schema type is an array (e.g., ["string", "null"])
     if (value === null && schemaType.includes('null')) {
       return []
     }
 
     for (const type of schemaType) {
+      if (type === 'array' && Array.isArray(value)) {
+        return [] // Correctly validate array type
+      }
       if (valueType === 'number' && type === 'integer' && Number.isInteger(value)) {
         return []
       }
-
       if (valueType === type || (type === 'null' && value === null)) {
         return []
       }
     }
   }
-
-  if (valueType === 'number' && schemaType === 'integer' && Number.isInteger(value)) {
-    return []
-  }
-
-  if (valueType === schemaType) {
-    return []
+  else {
+    // Handle cases where schema type is a single type string
+    if (schemaType === 'array' && Array.isArray(value)) {
+      return [] // Correctly validate array type
+    }
+    if (valueType === 'number' && schemaType === 'integer' && Number.isInteger(value)) {
+      return []
+    }
+    if (valueType === schemaType) {
+      return []
+    }
   }
 
+  // If none of the conditions matched, it's a type error
   return [{ path, validation: 'type' }]
 }
 
@@ -149,30 +158,36 @@ export function validateSchema(
   const valueIsUndefined = value === undefined || (value === null && options.treatNullAsUndefined)
   const errors: ValidationError[] = []
 
-  // If value is undefined but not required, no further validation needed
+  // Handle undefined value
   if (valueIsUndefined) {
     return []
   }
 
+  // Handle boolean schemas
   if (typeof schema === 'boolean') {
-    // It means the property does not exist in the payload
-    if (!schema && typeof value !== 'undefined') {
-      return [{ path, validation: 'valid' }]
-    }
-    else {
-      return []
-    }
+    return schema ? [] : [{ path, validation: 'valid' }]
   }
 
-  const typeValidationErrors = validateType(value, schema, path)
-  if (typeValidationErrors.length > 0) {
-    return typeValidationErrors
+  // Check if it is a file input (needed early for null check)
+  const presentation = schema['x-jsf-presentation']
+  const isExplicitFileInput = presentation?.inputType === 'file'
+
+  let typeValidationErrors: ValidationError[] = []
+  // Skip standard type validation ONLY if inputType is explicitly 'file'
+  // (The null check above already handled null for potential file inputs)
+  if (!isExplicitFileInput) {
+    typeValidationErrors = validateType(value, schema, path)
+    if (typeValidationErrors.length > 0) {
+      return typeValidationErrors
+    }
   }
 
   // If the schema defines "required", run required checks even when type is undefined.
   if (schema.required && isObjectValue(value)) {
     const missingKeys = schema.required.filter((key: string) => {
       const fieldValue = value[key]
+      // Field is considered missing if it's undefined OR
+      // if it's null AND treatNullAsUndefined option is true
       return fieldValue === undefined || (fieldValue === null && options.treatNullAsUndefined)
     })
 
@@ -193,6 +208,9 @@ export function validateSchema(
     ...validateArray(value, schema, options, jsonLogicBag, path),
     ...validateString(value, schema, path),
     ...validateNumber(value, schema, path),
+    // File validation
+    ...validateFile(value, schema, path),
+    // Composition and conditional logic
     ...validateNot(value, schema, options, jsonLogicBag, path),
     ...validateAllOf(value, schema, options, jsonLogicBag, path),
     ...validateAnyOf(value, schema, options, jsonLogicBag, path),