1 files changed, 33 insertions, 0 deletions
diff --git a/src/data/composite/data/withSum.js b/src/data/composite/data/withSum.js
new file mode 100644
index 00000000..484e9906
--- /dev/null
+++ b/src/data/composite/data/withSum.js
@@ -0,0 +1,33 @@
+// Gets the numeric total of adding all the values in a list together.
+// Values that are false, null, or undefined are skipped over.
+
+import {input, templateCompositeFrom} from '#composite';
+import {isNumber, sparseArrayOf} from '#validators';
+
+export default templateCompositeFrom({
+  annotation: `withSum`,
+
+  inputs: {
+    values: input({
+      validate: sparseArrayOf(isNumber),
+    }),
+  },
+
+  outputs: ['#sum'],
+
+  steps: () => [
+    {
+      dependencies: [input('values')],
+      compute: (continuation, {
+        [input('values')]: values,
+      }) => continuation({
+        ['#sum']:
+          values
+            .filter(item => typeof item === 'number')
+            .reduce(
+              (accumulator, value) => accumulator + value,
+              0),
+      }),
+    },
+  ],
+});