1 files changed, 32 insertions, 0 deletions
diff --git a/templates/assets/tether/src/js/shift.js b/templates/assets/tether/src/js/shift.js
new file mode 100644
index 0000000..ecc872d
--- /dev/null
+++ b/templates/assets/tether/src/js/shift.js
@@ -0,0 +1,32 @@
+/* globals TetherBase */
+
+TetherBase.modules.push({
+  position({top, left}) {
+    if (!this.options.shift) {
+      return;
+    }
+
+    let shift = this.options.shift;
+    if (typeof this.options.shift === 'function') {
+      shift = this.options.shift.call(this, {top, left});
+    }
+
+    let shiftTop, shiftLeft;
+    if (typeof shift === 'string') {
+      shift = shift.split(' ');
+      shift[1] = shift[1] || shift[0];
+
+      ([shiftTop, shiftLeft] = shift);
+
+      shiftTop = parseFloat(shiftTop, 10);
+      shiftLeft = parseFloat(shiftLeft, 10);
+    } else {
+      ([shiftTop, shiftLeft] = [shift.top, shift.left]);
+    }
+
+    top += shiftTop;
+    left += shiftLeft;
+
+    return {top, left};
+  }
+});