From f94498c05db375e2952f6f5ec29ce5cd2a8ac083 Mon Sep 17 00:00:00 2001
From: Dmitry Maganov <vonagam@gmail.com>
Date: Sun, 3 Feb 2019 17:17:07 +0300
Subject: [PATCH] feat: use a schema as when condition

---
 src/Condition.js | 17 +++++++++++++----
 test/mixed.js    | 29 ++++++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/src/Condition.js b/src/Condition.js
index d1ef6eed6..235d4db7d 100644
--- a/src/Condition.js
+++ b/src/Condition.js
@@ -7,6 +7,10 @@ function callOrConcat(schema) {
   return base => base.concat(schema);
 }
 
+function makeIsFn(refs, predicate) {
+  return refs.length < 2 ? predicate : (...values) => values.every(predicate);
+}
+
 class Conditional {
   constructor(refs, options) {
     let { is, then, otherwise } = options;
@@ -26,10 +30,15 @@ class Conditional {
           'either `then:` or `otherwise:` is required for `when()` conditions',
         );
 
-      let isFn =
-        typeof is === 'function'
-          ? is
-          : (...values) => values.every(value => value === is);
+      let isFn;
+
+      if (typeof is === 'function') {
+        isFn = is;
+      } else if (isSchema(is)) {
+        isFn = makeIsFn(this.refs, value => is.isValidSync(value));
+      } else {
+        isFn = makeIsFn(this.refs, value => value === is);
+      }
 
       this.fn = function(...values) {
         let currentSchema = values.pop();
diff --git a/test/mixed.js b/test/mixed.js
index 153f79ed3..4ca427791 100644
--- a/test/mixed.js
+++ b/test/mixed.js
@@ -1,4 +1,15 @@
-import { array, mixed, string, number, object, ref, reach, bool } from '../src';
+import {
+  array,
+  mixed,
+  string,
+  number,
+  object,
+  ref,
+  reach,
+  bool,
+  boolean,
+  ValidationError,
+} from '../src';
 let noop = () => {};
 
 function ensureSync(fn) {
@@ -701,6 +712,22 @@ describe('Mixed Types ', () => {
     inst.default().should.eql({ prop: undefined });
   });
 
+  it('should handle conditionals with schema as condition', async function() {
+    let inst = object({
+      flag: mixed(),
+      prop: number().when('flag', {
+        is: boolean(),
+        then: number().min(5),
+      }),
+    });
+
+    await inst.validate({ flag: 'hello', prop: 4 }).should.be.fulfilled();
+
+    await inst
+      .validate({ flag: true, prop: 4 })
+      .should.be.rejectedWith(ValidationError, /must be greater than/);
+  });
+
   it('should use label in error message', async function() {
     let label = 'Label';
     let inst = object({