From c5cc845c9b11bd6f3361f8fe4c7bb6c7addfdb1c Mon Sep 17 00:00:00 2001
From: nlepage <19571875+nlepage@users.noreply.github.com>
Date: Fri, 5 Jan 2018 14:08:30 +0100
Subject: [PATCH] :recycle: Toleration falsey args in flow fix #202

---
 packages/immutadot/src/flow/flow.js      |  6 +++--
 packages/immutadot/src/flow/flow.spec.js | 33 ++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/packages/immutadot/src/flow/flow.js b/packages/immutadot/src/flow/flow.js
index b8651254..f5f68161 100644
--- a/packages/immutadot/src/flow/flow.js
+++ b/packages/immutadot/src/flow/flow.js
@@ -1,4 +1,5 @@
 import { flatten } from 'util/array'
+import { isNil } from 'util/lang'
 
 /**
  * A function successively applying a list of functions.
@@ -11,14 +12,15 @@ import { flatten } from 'util/array'
 
 /**
  * Successively calls <code>fns</code>.<br/>
- * Each function is called with the result of the previous one.
+ * Each function is called with the result of the previous one.<br/>
+ * Falsey functions (<code>null</code>, <code>undefined</code> and <code>false</code>) are tolerated and will be skipped.
  * @memberof flow
  * @param {...(function|Array<function>)} args The functions to apply
  * @returns {flow.flowFunction} A function successively calling <code>fns</code>
  * @since 1.0.0
  */
 function flow(...args) {
-  const fns = flatten(args)
+  const fns = flatten(args).filter(fn => !isNil(fn) && fn !== false)
   return pObj => {
     const [result] = fns.reduce(
       ([obj, appliedPaths], fn) => [
diff --git a/packages/immutadot/src/flow/flow.spec.js b/packages/immutadot/src/flow/flow.spec.js
index 6cfc76bf..a05e943b 100644
--- a/packages/immutadot/src/flow/flow.spec.js
+++ b/packages/immutadot/src/flow/flow.spec.js
@@ -74,4 +74,37 @@ describe('flow.flow', () => {
       return output
     }, object, 'nested1.prop2', 'nested2.prop3', 'nested2.prop4')
   })
+
+  it('should skip falsey functions', () => {
+    immutaTest((input, path) => {
+      const output = flow(
+        null,
+        set(path, 'bar'),
+        undefined,
+        false,
+        [
+          null,
+          undefined,
+          false,
+        ],
+      )(input)
+      expect(output).toEqual({
+        nested: { prop: 'bar' },
+        other: {},
+      })
+      return output
+    }, {
+      nested: { prop: 'foo' },
+      other: {},
+    }, 'nested.prop')
+  })
+
+  it('should do nothing if empty flow', () => {
+    const input = {
+      nested: { prop: 'foo' },
+      other: {},
+    }
+    const output = flow()(input)
+    expect(output).toBe(input)
+  })
 })