fix: Accept null inputs in curried functions

Author: justinvdm

join.js

@@ -1,9 +1,7 @@
 var tuple = require('./tuple')
 
 function join(a, b, c) {
-  return a != null && b != null && c == null
-    ? joinCurried(a, b)
-    : joinMain(a, b, c)
+  return b != null && c == null ? joinCurried(a, b) : joinMain(a, b, c)
 }
 
 function joinMain(id, joiner, makerFns) {

tests/fictional.test.js

@@ -54,6 +54,7 @@ tap.test('consistency', t => {
 tap.test('curried makers', t => {
   for (const [fn, ...args] of curriedMakerDefs) {
     t.deepEquals(fn(23, ...args), fn(...args)(23))
+    t.deepEquals(fn(null, ...args), fn(...args)(null))
   }
 
   t.end()

tuple.js

@@ -1,7 +1,7 @@
 var hash = require('./hash')
 
 function tuple(a, b) {
-  return a != null && b != null ? tupleMain(a, b) : tupleCurried(a)
+  return b != null ? tupleMain(a, b) : tupleCurried(a)
 }
 
 function tupleMain(input, fns) {