Bump to v4.0.0.

concat.js

@@ -0,0 +1,32 @@
+import arrayConcat from './internal/arrayConcat';
+import baseFlatten from './internal/baseFlatten';
+import isArray from './isArray';
+import rest from './rest';
+
+/**
+ * Creates a new array concatenating `array` with any additional arrays
+ * and/or values.
+ *
+ * @static
+ * @memberOf _
+ * @category Array
+ * @param {Array} array The array to concatenate.
+ * @param {...*} [values] The values to concatenate.
+ * @returns {Array} Returns the new concatenated array.
+ * @example
+ *
+ * var array = [1];
+ * var other = _.concat(array, 2, [3], [[4]]);
+ *
+ * console.log(other);
+ * // => [1, 2, 3, [4]]
+ *
+ * console.log(array);
+ * // => [1]
+ */
+var concat = rest(function(array, values) {
+  values = baseFlatten(values);
+  return arrayConcat(isArray(array) ? array : [Object(array)], values);
+});
+
+export default concat;