feat: implement requiredIf rules

src/schema/base/literal.ts

@@ -17,10 +17,13 @@ import type {
   Validation,
   RuleBuilder,
   Transformer,
+  FieldContext,
   FieldOptions,
   ParserOptions,
   ConstructableSchema,
 } from '../../types.js'
+import { requiredWhen } from './rules.js'
+import { helpers } from '../../vine/helpers.js'
 
 /**
  * Base schema type with only modifiers applicable on all the schema types.
@@ -51,8 +54,8 @@ abstract class BaseModifiersType<Output, CamelCaseOutput>
    * Mark the field under validation as optional. An optional
    * field allows both null and undefined values.
    */
-  optional(): OptionalModifier<this> {
-    return new OptionalModifier(this)
+  optional(validations?: Validation<any>[]): OptionalModifier<this> {
+    return new OptionalModifier(this, validations)
   }
 
   /**
@@ -85,9 +88,16 @@ class NullableModifier<Schema extends BaseModifiersType<any, any>> extends BaseM
   Schema[typeof COTYPE] | null
 > {
   #parent: Schema
-  constructor(parent: Schema) {
+
+  /**
+   * Optional modifier validations list
+   */
+  validations: Validation<any>[]
+
+  constructor(parent: Schema, validations?: Validation<any>[]) {
     super()
     this.#parent = parent
+    this.validations = validations || []
   }
 
   /**
@@ -116,17 +126,134 @@ class OptionalModifier<Schema extends BaseModifiersType<any, any>> extends BaseM
   Schema[typeof COTYPE] | undefined
 > {
   #parent: Schema
-  constructor(parent: Schema) {
+
+  /**
+   * Optional modifier validations list
+   */
+  validations: Validation<any>[]
+
+  constructor(parent: Schema, validations?: Validation<any>[]) {
     super()
     this.#parent = parent
+    this.validations = validations || []
+  }
+
+  /**
+   * Shallow clones the validations. Since, there are no API's to mutate
+   * the validation options, we can safely copy them by reference.
+   */
+  protected cloneValidations(): Validation<any>[] {
+    return this.validations.map((validation) => {
+      return {
+        options: validation.options,
+        rule: validation.rule,
+      }
+    })
+  }
+
+  /**
+   * Compiles validations
+   */
+  protected compileValidations(refs: RefsStore) {
+    return this.validations.map((validation) => {
+      return {
+        ruleFnId: refs.track({
+          validator: validation.rule.validator,
+          options: validation.options,
+        }),
+        implicit: validation.rule.implicit,
+        isAsync: validation.rule.isAsync,
+      }
+    })
+  }
+
+  /**
+   * Push a validation to the validations chain.
+   */
+  use(validation: Validation<any> | RuleBuilder): this {
+    this.validations.push(VALIDATION in validation ? validation[VALIDATION]() : validation)
+    return this
+  }
+
+  /**
+   * Define a callback to conditionally require a field at
+   * runtime.
+   *
+   * The callback method should return "true" to mark the
+   * field as required, or "false" to skip the required
+   * validation
+   */
+  requiredWhen(callback: (field: FieldContext) => boolean) {
+    return this.use(requiredWhen(callback))
+  }
+
+  /**
+   * Mark the field under validation as required when all
+   * the other fields are present with value other
+   * than `undefined` or `null`.
+   */
+  requiredIfExists(fields: string | string[]) {
+    const fieldsToExist = Array.isArray(fields) ? fields : [fields]
+    return this.use(
+      requiredWhen((field) => {
+        return fieldsToExist.every((otherField) =>
+          helpers.exists(helpers.getNestedValue(otherField, field))
+        )
+      })
+    )
+  }
+
+  /**
+   * Mark the field under validation as required when any
+   * one of the other fields are present with non-nullable
+   * value.
+   */
+  requiredIfExistsAny(fields: string[]) {
+    return this.use(
+      requiredWhen((field) => {
+        return fields.some((otherField) =>
+          helpers.exists(helpers.getNestedValue(otherField, field))
+        )
+      })
+    )
+  }
+
+  /**
+   * Mark the field under validation as required when all
+   * the other fields are missing or their value is
+   * `undefined` or `null`.
+   */
+  requiredIfMissing(fields: string | string[]) {
+    const fieldsToExist = Array.isArray(fields) ? fields : [fields]
+    return this.use(
+      requiredWhen((field) => {
+        return fieldsToExist.every((otherField) =>
+          helpers.isMissing(helpers.getNestedValue(otherField, field))
+        )
+      })
+    )
+  }
+
+  /**
+   * Mark the field under validation as required when any
+   * one of the other fields are missing.
+   */
+  requiredIfMissingAny(fields: string[]) {
+    return this.use(
+      requiredWhen((field) => {
+        return fields.some((otherField) =>
+          helpers.isMissing(helpers.getNestedValue(otherField, field))
+        )
+      })
+    )
   }
 
   /**
    * Creates a fresh instance of the underlying schema type
    * and wraps it inside the optional modifier
    */
   clone(): this {
-    return new OptionalModifier(this.#parent.clone()) as this
+    return new OptionalModifier(this.#parent.clone(), this.cloneValidations()) as this
   }
 
   /**
@@ -135,6 +262,7 @@ class OptionalModifier<Schema extends BaseModifiersType<any, any>> extends BaseM
   [PARSE](propertyName: string, refs: RefsStore, options: ParserOptions): LiteralNode {
     const output = this.#parent[PARSE](propertyName, refs, options)
     output.isOptional = true
+    output.validations = output.validations.concat(this.compileValidations(refs))
     return output
   }
 }

src/schema/base/rules.ts

@@ -0,0 +1,28 @@
+/*
+ * @vinejs/vine
+ *
+ * (c) VineJS
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+import { messages } from '../../defaults.js'
+import type { FieldContext } from '../../types.js'
+import { createRule } from '../../vine/create_rule.js'
+
+/**
+ * Validates the value to be required when a certain condition
+ * is matched
+ */
+export const requiredWhen = createRule<(field: FieldContext) => boolean>(
+  (_, checker, field) => {
+    const shouldBeRequired = checker(field)
+    if (!field.isDefined && shouldBeRequired) {
+      field.report(messages.required, 'required', field)
+    }
+  },
+  {
+    implicit: true,
+  }
+)