Move internal modules to “internal” folder.

.internal/baseRepeat.js

@@ -0,0 +1,35 @@
+/** Used as references for various `Number` constants. */
+const MAX_SAFE_INTEGER = 9007199254740991;
+
+/* Built-in method references for those with the same name as other `lodash` methods. */
+const nativeFloor = Math.floor;
+
+/**
+ * The base implementation of `repeat` which doesn't coerce arguments.
+ *
+ * @private
+ * @param {string} string The string to repeat.
+ * @param {number} n The number of times to repeat the string.
+ * @returns {string} Returns the repeated string.
+ */
+function baseRepeat(string, n) {
+  let result = '';
+  if (!string || n < 1 || n > MAX_SAFE_INTEGER) {
+    return result;
+  }
+  // Leverage the exponentiation by squaring algorithm for a faster repeat.
+  // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
+  do {
+    if (n % 2) {
+      result += string;
+    }
+    n = nativeFloor(n / 2);
+    if (n) {
+      string += string;
+    }
+  } while (n);
+
+  return result;
+}
+
+export default baseRepeat;