1 files changed, 35 insertions, 0 deletions
diff --git a/app/assets/javascripts/vue_shared/components/lib/utils/props_utils.js b/app/assets/javascripts/vue_shared/components/lib/utils/props_utils.js
new file mode 100644
index 00000000000..b115b1fb34b
--- /dev/null
+++ b/app/assets/javascripts/vue_shared/components/lib/utils/props_utils.js
@@ -0,0 +1,35 @@
+/**
+ * Return the union of the given components' props options. Required props take
+ * precendence over non-required props of the same name.
+ *
+ * This makes two assumptions:
+ *  - All given components define their props in verbose object format.
+ *  - The components all agree on the `type` of a common prop.
+ *
+ * @param {object[]} components The components to derive the union from.
+ * @returns {object} The union of the props of the given components.
+ */
+export const propsUnion = (components) =>
+  components.reduce((acc, component) => {
+    Object.entries(component.props ?? {}).forEach(([propName, propOptions]) => {
+      if (process.env.NODE_ENV !== 'production') {
+        if (typeof propOptions !== 'object' || !('type' in propOptions)) {
+          throw new Error(
+            `Cannot create props union: expected verbose prop options for prop "${propName}"`,
+          );
+        }
+
+        if (propName in acc && acc[propName]?.type !== propOptions?.type) {
+          throw new Error(
+            `Cannot create props union: incompatible prop types for prop "${propName}"`,
+          );
+        }
+      }
+
+      if (!(propName in acc) || propOptions.required) {
+        acc[propName] = propOptions;
+      }
+    });
+
+    return acc;
+  }, {});