factor out util.js

1 files changed, 35 insertions, 0 deletions

diff --git a/scripts/util.js b/scripts/util.js
new file mode 100644
index 00000000..4eb94266
--- /dev/null
+++ b/scripts/util.js
@@ -0,0 +1,35 @@
+function set_from_array(a) {
+    var ret = {};
+    for (var k = 0 ; k < a.length ; ++k) {
+        ret[a[k]] = 1;
+    }
+    return ret;
+}
+
+function set_diff(sa, sb) {
+    var ret = {a_b:[], b_a:[]};
+    var i;
+    for (i in sa) {
+        if (!(i in sb)) {
+            ret.a_b.push(i);
+        }
+    }
+    for (i in sb) {
+        if (!(i in sa)) {
+            ret.b_a.push(i);
+        }
+    }
+    return ret;
+}
+
+function array_diff(aa, ab) {
+    var sa = set_from_array(aa);
+    var sb = set_from_array(ab);
+    return set_diff(sa, sb);
+}
+
+if (typeof(exports) != 'undefined') {
+    exports.set_diff = set_diff;
+    exports.array_diff = array_diff;
+    exports.set_from_array = set_from_array;
+}