From 6836265e9d5410eb5a8cff8a86049369355da35e Mon Sep 17 00:00:00 2001
From: Vahn Gomes <me@vahngomes.dev>
Date: Fri, 15 Mar 2024 21:20:07 -0400
Subject: [PATCH] Refactor requiredWhen validation logic

---
 __tests__/validator.test.ts | 68 +++++++++++++++++++++++++++++++++++++
 src/index.ts                | 40 +++++++++++++---------
 2 files changed, 92 insertions(+), 16 deletions(-)

diff --git a/__tests__/validator.test.ts b/__tests__/validator.test.ts
index 13ab36e..814080f 100644
--- a/__tests__/validator.test.ts
+++ b/__tests__/validator.test.ts
@@ -182,6 +182,74 @@ describe("Validator - Required When Validation", () => {
     );
     expect(validator.validate({ age: 18 })).resolves.toBe(false);
   });
+
+  it("should validate requiredWhen fields with multiple fields", () => {
+    const validator = new Validator(
+      {
+        name: {
+          type: "string",
+          requiredWhen: [
+            { field: "age", value: 18 },
+            { field: "age", value: 20 },
+          ],
+        },
+        age: { type: "number" },
+      },
+      {
+        name: {
+          type: "Name must be a string",
+          requiredWhen: "Name is required",
+        },
+        age: {
+          type: "Age must be a number",
+        },
+      }
+    );
+
+    expect(validator.validate({ name: "John Doe", age: 18 })).resolves.toBe(
+      true
+    );
+    expect(validator.validate({ name: "John Doe", age: 20 })).resolves.toBe(
+      true
+    );
+    expect(validator.validate({ age: 18 })).resolves.toBe(false);
+  });
+
+  it("should validate requiredWhen fields with multiple fields and values", () => {
+    const validator = new Validator(
+      {
+        name: {
+          type: "string",
+          requiredWhen: [
+            { field: "age", value: [18, 20] },
+            { field: "active", value: true },
+          ],
+        },
+        age: { type: "number" },
+        active: { type: "boolean" },
+      },
+      {
+        name: {
+          type: "Name must be a string",
+          requiredWhen: "Name is required",
+        },
+        age: {
+          type: "Age must be a number",
+        },
+        active: {
+          type: "Active must be a boolean",
+        },
+      }
+    );
+
+    expect(
+      validator.validate({ name: "John Doe", age: 18, active: true })
+    ).resolves.toBe(true);
+    expect(
+      validator.validate({ name: "John Doe", age: 20, active: true })
+    ).resolves.toBe(true);
+    expect(validator.validate({ age: 18, active: true })).resolves.toBe(false);
+  });
 });
 
 describe("Validator - Min/Max Validation", () => {
diff --git a/src/index.ts b/src/index.ts
index 965ae16..f38abf0 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -45,7 +45,9 @@ interface Rule {
   /**
    * Field is required when another field matches a specific value.
    */
-  requiredWhen?: { field: string; value: any | any[] };
+  requiredWhen?:
+    | { field: string; value: any | any[] }
+    | Array<{ field: string; value: any | any[] }>;
 }
 
 /**
@@ -265,27 +267,33 @@ class Validator {
 
       // Handle requiredWhen condition
       if (rule.requiredWhen) {
-        const conditionField = rule.requiredWhen.field;
-        const conditionValue = rule.requiredWhen.value;
         let conditionMet = false;
 
-        // Check if conditionValue is an array and if it includes the input value
-        if (Array.isArray(conditionValue)) {
-          conditionMet = conditionValue.includes(input[conditionField]);
-        } else {
-          // If conditionValue is not an array, proceed with the normal equality check
-          conditionMet = input[conditionField] === conditionValue;
+        // Convert single condition to array for unified processing
+        const conditions = Array.isArray(rule.requiredWhen)
+          ? rule.requiredWhen
+          : [rule.requiredWhen];
+
+        for (const condition of conditions) {
+          const conditionField = condition.field;
+          const conditionValue = condition.value;
+          const inputValue = input[conditionField];
+
+          // Check if the condition is met (supports value being an array)
+          if (Array.isArray(conditionValue)) {
+            conditionMet = conditionValue.includes(inputValue);
+          } else {
+            conditionMet = inputValue === conditionValue;
+          }
+
+          if (conditionMet) break; // Stop checking further conditions if one is met
         }
 
-        // If the condition is met and the field is required but not present or empty
+        // If any condition is met and the field is required but not present or empty
         if (conditionMet && (value === "" || value === undefined)) {
           this.errors[key] =
-            this.messages[key].required ??
-            `"${key}" is required when "${conditionField}" is set to ${
-              Array.isArray(conditionValue)
-                ? conditionValue.join(" or ")
-                : conditionValue
-            }.`;
+            this.messages[key].requiredWhen ??
+            `"${key}" is required based on the current conditions.`;
           isValid = false;
           continue; // Skip further checks for this field
         }