feat: add object-utils with deepMerge

npm/ng-packs/packages/core/src/lib/utils/object-utils.ts

@@ -0,0 +1,51 @@
+export function deepMerge(target, source) {
+  if (isObjectAndNotArray(target) && isObjectAndNotArray(source)) {
+    return deepMergeRecursively(target, source);
+  } else if (isNullOrUndefined(target) && isNullOrUndefined(source)) {
+    return {};
+  } else {
+    return isNullOrUndefined(source) ? target : source;
+  }
+}
+
+function deepMergeRecursively(target, source) {
+  const shouldNotRecurse =
+    isNullOrUndefined(target) ||
+    isNullOrUndefined(source) || // at least one not defined
+    isArray(target) ||
+    isArray(source) || // at least one array
+    !isObject(target) ||
+    !isObject(source); // at least one not an object;
+
+  /**
+   * if we will not recurse any further,
+   * we will prioritize source if it is a defined value.
+   */
+  if (shouldNotRecurse) {
+    return !isNullOrUndefined(source) ? source : target;
+  }
+
+  const keysOfTarget = Object.keys(target);
+  const keysOfSource = Object.keys(source);
+  const uniqueKeys = new Set(keysOfTarget.concat(keysOfSource));
+  return [...uniqueKeys].reduce((retVal, key) => {
+    retVal[key] = deepMergeRecursively(target[key], source[key]);
+    return retVal;
+  }, {});
+}
+
+function isNullOrUndefined(obj) {
+  return obj === null || obj === undefined;
+}
+
+function isObject(obj) {
+  return obj instanceof Object;
+}
+
+function isArray(obj) {
+  return Array.isArray(obj);
+}
+
+function isObjectAndNotArray(obj) {
+  return isObject(obj) && !isArray(obj);
+}