From 932da9f7d5863e0ff0a4d3a6073522c1fd93c5b5 Mon Sep 17 00:00:00 2001
From: Andy Brown <asbrown002@gmail.com>
Date: Fri, 21 Aug 2015 09:09:18 -0700
Subject: [PATCH] report correct arity for curried functions

fixes #31
---
 lib/util/curry.js       |  8 ++++----
 test/util/curry-spec.js | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/lib/util/curry.js b/lib/util/curry.js
index 036a66d..2f9157c 100644
--- a/lib/util/curry.js
+++ b/lib/util/curry.js
@@ -13,7 +13,7 @@ function countArguments(args, max) {
 }
 
 export function curry1(fn) {
-  return function curried(a, b, c) {
+  return function curried(a, ...[b, c]) {
     const n = countArguments(arguments);
 
     if (n >= 1) return fn(a, b, c);
@@ -22,7 +22,7 @@ export function curry1(fn) {
 }
 
 export function curry2(fn) {
-  return function curried(a, b, c, d) {
+  return function curried(a, b, ...[c, d]) {
     const n = countArguments(arguments, 2);
 
     if (b === _ || c === _ || d === _) {
@@ -40,7 +40,7 @@ export function curry2(fn) {
 }
 
 export function curry3(fn) {
-  return function curried(a, b, c, d, e) {
+  return function curried(a, b, c, ...[d, e]) {
     const n = countArguments(arguments, 3);
 
     if (c === _ || d === _ || e === _) {
@@ -68,7 +68,7 @@ export function curry3(fn) {
 }
 
 export function curry4(fn) {
-  return function curried(a, b, c, d, e, f) {
+  return function curried(a, b, c, d, ...[e, f]) {
     const n = countArguments(arguments, 4);
 
     if (d === _ || e === _ || f === _) {
diff --git a/test/util/curry-spec.js b/test/util/curry-spec.js
index 69b66c8..f43f03d 100644
--- a/test/util/curry-spec.js
+++ b/test/util/curry-spec.js
@@ -12,6 +12,11 @@ describe('curry1', () => {
     const curried = curry1((a, b, c) => [a, b, c]);
     expect(curried(1, 2, 3, 4)).to.eql([1, 2, 3]);
   });
+
+  it('returns a fn with arity of 1', () => {
+    const curried = curry1((a, b, c) => [a, b, c]);
+    expect(curried).to.have.length(1);
+  });
 });
 
 describe('curry2', () => {
@@ -31,6 +36,11 @@ describe('curry2', () => {
     const curried = curry2((a, b, c, d) => [a, b, c, d]);
     expect(curried(_, 2)(1, 3, 4)).to.eql([1, 2, 3, 4]);
   });
+
+  it('returns a fn with arity of 2', () => {
+    const curried = curry2((a, b, c, d) => [a, b, c, d]);
+    expect(curried).to.have.length(2);
+  });
 });
 
 describe('curry3', () => {
@@ -53,6 +63,11 @@ describe('curry3', () => {
     expect(curried(_, 2, 3)('c', 4, 5)).to.eql(['c', 2, 3, 4, 5]);
     expect(curried(_, _, 3)('d', 2, 4, 5)).to.eql(['d', 2, 3, 4, 5]);
   });
+
+  it('returns a fn with arity of 3', () => {
+    const curried = curry3((a, b, c, d, e) => [a, b, c, d, e]);
+    expect(curried).to.have.length(3);
+  });
 });
 
 describe('curry4', () => {
@@ -87,4 +102,9 @@ describe('curry4', () => {
 
     expect(curried(_, _, _, 4)('k', 2, 3, 5, 6)).to.eql(['k', 2, 3, 4, 5, 6]);
   });
+
+  it('returns a fn with arity of 4', () => {
+    const curried = curry4((a, b, c, d, e, f) => [a, b, c, d, e, f]);
+    expect(curried).to.have.length(4);
+  });
 });