1 files changed, 5 insertions, 0 deletions
diff --git a/popperjs/package/lib/utils/getAltLen.js.flow b/popperjs/package/lib/utils/getAltLen.js.flow
new file mode 100644
index 0000000..ad484da
--- /dev/null
+++ b/popperjs/package/lib/utils/getAltLen.js.flow
@@ -0,0 +1,5 @@
+// @flow
+
+export default function getAltLen(len: 'width' | 'height'): 'width' | 'height' {
+  return len === 'width' ? 'height' : 'width';
+}