fix(pickIndexes): omits values for non existing indexes

Closes char0n#181
srghma · Jan 13, 2018 · 6e4b9b3 · 6e4b9b3
1 parent 2881bd6
commit 6e4b9b3
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Showing 2 changed files with 32 additions and 10 deletions.
diff --git a/src/pickIndexes.js b/src/pickIndexes.js
@@ -1,4 +1,10 @@
-import { curryN, compose, values, pickAll } from 'ramda';
+import { filter, addIndex, curry, contains } from 'ramda';
+
+
+// helpers
+const filterIndexed = addIndex(filter);
+const containsIndex = curry((indexes, val, index) => contains(index, indexes));
+
 
 /**
  * Picks values from list by indexes.
@@ -16,6 +22,6 @@ import { curryN, compose, values, pickAll } from 'ramda';
  *
  * RA.pickIndexes([0, 2], ['a', 'b', 'c']); //=> ['a', 'c']
  */
-const pickIndexes = curryN(2, compose(values, pickAll));
+const pickIndexes = curry((indexes, list) => filterIndexed(containsIndex(indexes), list));
 
 export default pickIndexes;
diff --git a/test/pickIndexes.js b/test/pickIndexes.js
@@ -5,23 +5,39 @@ import eq from './shared/eq';
 
 
 describe('pickIndexes', function() {
+  let list;
+
+  beforeEach(function() {
+    list = ['a', 'b', 'c'];
+  });
+
   it('tests picking values from list by indexes', function() {
-    eq(RA.pickIndexes([0, 2], ['a', 'b', 'c']), ['a', 'c']);
+    eq(RA.pickIndexes([0, 2], list), ['a', 'c']);
   });
 
   it('tests currying', function() {
-    eq(RA.pickIndexes([0, 2])(['a', 'b', 'c']), ['a', 'c']);
+    eq(RA.pickIndexes([], []), []);
+    eq(RA.pickIndexes([])([]), []);
   });
 
-  it('tests picking values from list by indexes out of range', function() {
-    eq(RA.pickIndexes([0, 5], ['a', 'b', 'c']), ['a', undefined]);
+
+  context("when indexes doesn't exist", function() {
+    specify('should skip these indexes', function() {
+      eq(RA.pickIndexes([-1, 0, 5], list), ['a']);
+    });
   });
 
-  it('tests picking values from list by non array', function() {
-    chai.assert.throws(RA.pickIndexes.bind(null, undefined, ['a', 'b', 'c']), TypeError);
+  // todo fix function parens inconsistencies
+  context('when indexes is a non-array', function() {
+    it('should produce TypeError', function() {
+      chai.assert.throws(RA.pickIndexes.bind(null, undefined, list), TypeError);
+    });
   });
 
-  it('tests picking values from non-array', function() {
-    chai.assert.throws(RA.pickIndexes.bind(null, [0, 2], undefined), TypeError);
+
+  context('when list is a non-array', function() {
+    it('should product TypeError', function() {
+      chai.assert.throws(RA.pickIndexes.bind(null, [0, 2], undefined), TypeError);
+    });
   });
 });