add method defaultTo

README.md

@@ -162,7 +162,7 @@ fn = R.cond([
 - [x] 0.1.2 curry
 - [x] 0.1.2 curryN
 - [ ] dec
-- [ ] defaultTo
+- [x] defaultTo
 - [ ] descend
 - [x] 0.1.2 difference
 - [x] 0.1.2 differenceWith

ramda/__init__.py

@@ -20,6 +20,7 @@
 from .countBy import countBy
 from .curry import curry
 from .curryN import curryN
+from .defaultTo import defaultTo
 from .difference import difference
 from .differenceWith import differenceWith
 from .divide import divide

ramda/defaultTo.py

@@ -0,0 +1,3 @@
+from .private._curry2 import _curry2
+
+defaultTo = _curry2(lambda d, v: d if v is None else v)

test/test_defaultTo.py

@@ -0,0 +1,30 @@
+
+import unittest
+
+import ramda as R
+
+"""
+https://github.com/ramda/ramda/blob/master/test/defaultTo.js
+"""
+
+defaultTo42 = R.defaultTo(42)
+
+class TestDefaultTo(unittest.TestCase):
+  def test_returns_the_default_value_if_input_is_None(self):
+    self.assertEqual(42, defaultTo42(None))
+
+  def test_returns_the_input_value_if_it_is_not_None(self):
+    self.assertEqual('a real value', defaultTo42('a real value'))
+
+  def test_returns_the_input_value_even_if_it_is_considered_falsy(self):
+    self.assertEqual('', defaultTo42(''))
+    self.assertEqual(0, defaultTo42(0))
+    self.assertEqual(False, defaultTo42(False))
+    self.assertEqual([], defaultTo42([]))
+
+  def test_can_be_called_with_both_arguments_directly(self):
+    self.assertEqual(42, R.defaultTo(42, None))
+    self.assertEqual('a real value', R.defaultTo(42, 'a real value'))
+
+if __name__ == '__main__':
+  unittest.main()