feat: added removeN() operation

src/operations/index.js

@@ -1,6 +1,7 @@
 const update = require('./update');
 const set = require('./set');
 const remove = require('./remove');
+const removeN = require('./removeN');
 const push = require('./push');
 const pushAll = require('./pushAll');
 const pop = require('./pop');
@@ -14,6 +15,7 @@ module.exports = {
     update,
     set,
     remove,
+    removeN,
     push,
     pushAll,
     pop,

src/operations/removeN/index.js

@@ -0,0 +1,56 @@
+const { updateArray, isNumber, extractSubPath } = require('../common');
+
+module.exports = removeN;
+
+/**
+ * Removes number of elements from array-item selected by path
+ * @param {Object | any[]} object object to update
+ * @param {string | string[]} path path to first item to be removed
+ * (array of items or dot-separated string can be provided)
+ * @param {number} n number of items to remove
+ * @returns {Object | any[]} updated object
+ * @description one of additional functions to work with array items
+ * @docs
+ * ```js
+ * import { removeN } from 'immutable-object-update';
+ *
+ * const state = {
+ *     a: {
+ *         b: [ 1, 2, 3, 4, 5, 6 ]
+ *     },
+ * };
+ *
+ * const updated = removeN(state, [ 'a', 'b', 1 ], 3);
+ *
+ * // or
+ *
+ * const updated = removeN(state, 'b.b1.1', 3);
+ * ```
+ *
+ * As a result we will receive new object with structure below:
+ *
+ * ```js
+ * {
+ *     a: {
+ *         b: [ 1, 5, 6 ]
+ *     }
+ * }
+ * ```
+ *
+ * > Please note: `removeN()` function won't return removed items
+ */
+function removeN(object, path, n) {
+    const [ itemPath, valuePath ] = extractSubPath(path);
+
+    if (!isNumber(valuePath)) {
+        return object;
+    }
+
+    return updateArray(
+        object,
+        itemPath,
+        array => array
+            .slice(0, valuePath)
+            .concat(array.slice(+valuePath + n))
+    );
+}