feat(add-object-property): new function with unit tests for adding a …

…new property to an object

index.js

@@ -9,6 +9,7 @@ const sortArrayByKey = require("./util/sortArrayByKey");
 const mergeObjects = require("./util/mergeObjects");
 const sizeOfObject = require("./util/sizeOfObject");
 const onlyUniqueValues = require("./util/onlyUniqueValues");
+const addObjectProperty = require("./util/addObjectProperty");
 
 module.exports = {
     removeFromString,
@@ -21,5 +22,6 @@ module.exports = {
     sortArrayByKey,
     mergeObjects,
     sizeOfObject,
-    onlyUniqueValues
+    onlyUniqueValues,
+    addObjectProperty
 };

test/polyfig.js

@@ -182,4 +182,19 @@ describe("polyfig", function () {
             outcome.should.eqls([1, 2, 3, "1", "3", "2"]);
         });
     });
+
+    describe("addObjectProperty", function () {
+        it("should exist as a method", function () {
+            expect(polyfig.addObjectProperty).to.exist;
+        });
+
+        it("should add a new property to an object", function () {
+            let x = {};
+            let y = "poly";
+            let z = ["fig"];
+            polyfig.addObjectProperty(x, y, z);
+            let outcome = x;
+            outcome.should.eqls({ poly: ["fig"] });
+        });
+    });
 });

util/addObjectProperty.js

@@ -0,0 +1,28 @@
+/**
+ *
+ * @name addObjectProperty
+ *
+ * @summary How do you add a key-value pair or new property to an object?
+ *
+ * @since 1.3.0
+ *
+ * @category Object
+ *
+ * @param {Object} x - Object to add new property to
+ * @param {string} y - Property name
+ * @param {any} z - Property value
+ *
+ * @return {Object} Provided object with new property added
+ *
+ * @example
+ * => polyfig.addObjectProperty({}, "poly", ["fig"]);
+ * => {"poly": ["fig"]}
+ */
+
+function addObjectProperty(x, y, z) {
+    return typeof x === "object" && x !== null && typeof y === "string"
+        ? (x[y] = z)
+        : new Error("x is not of type object or y is not of type string");
+}
+
+module.exports = addObjectProperty;