[feat #45] - filter (#86)

closes #45

core.js

@@ -316,6 +316,16 @@ export function map(f, coll) {
   return ret;
 }
 
+export function filter(pred, coll) {
+  let ret = [];
+  for (const x of iterable(coll)) {
+    if (pred(x)) {
+      ret.push(x);
+    }
+  }
+  return ret;
+}
+
 export function map_indexed(f, coll) {
   let ret = [];
   let i = 0;

resources/clava/core.edn

@@ -1 +1 @@
-#{seq reduce first dissoc atom dec map assoc_in reset_BANG_ rest PROTOCOL_SENTINEL _PLUS_ reduced_QMARK_ range disj seqable_QMARK_ iterable conj get disj_BANG_ vec second prn odd_QMARK_ assoc_BANG_ println Atom nth nil_QMARK_ assoc_in_BANG_ dissoc_BANG_ not pr_str swap_BANG_ vector mapv subvec reduced even_QMARK_ inc str apply map_indexed deref assoc complement constantly conj_BANG_ re_matches}
+#{seq reduce first dissoc atom dec map assoc_in reset_BANG_ rest PROTOCOL_SENTINEL _PLUS_ reduced_QMARK_ range disj seqable_QMARK_ iterable conj get disj_BANG_ vec second prn odd_QMARK_ assoc_BANG_ println Atom nth nil_QMARK_ assoc_in_BANG_ dissoc_BANG_ not pr_str swap_BANG_ vector mapv subvec reduced even_QMARK_ inc filter str apply map_indexed deref assoc complement constantly conj_BANG_ re_matches}

test/clava/compiler_test.cljs

@@ -663,6 +663,15 @@
     (is (eq () (jsv! '(map inc nil))))
     (is (eq () (jsv! '(map inc js/undefined))))))
 
+(deftest filter-test
+  (is (eq [2 4 6 8] (jsv! '(filter even? [1 2 3 4 5 6 7 8 9]))))
+  (is (every? (set (jsv! '(filter even? #{1 2 3 4 5 6 7 8 9})))
+        [2 4 6 8]))
+  (is (eq [[:a 1]] (jsv! '(filter #(= :a (first %)) {:a 1 :b 2}))))
+  (testing "nil"
+    (is (eq () (jsv! '(filter even? nil))))
+    (is (eq () (jsv! '(filter even? js/undefined))))))
+
 (deftest map-indexed-test
   (is (eq [[0 0] [1 1] [2 2] [3 3] [4 4]]
           (jsv! '(map-indexed vector [0 1 2 3 4]))))