chore: add warning for invalid usage, close: #91

package.json

@@ -52,6 +52,7 @@
   "dependencies": {
     "classnames": "^2.2.1",
     "rc-tooltip": "3.x",
-    "rc-util": "3.x"
+    "rc-util": "3.x",
+    "warning": "^2.1.0"
   }
-}
+}

src/Steps.jsx

@@ -1,7 +1,9 @@
 import React from 'react';
 import classNames from 'classnames';
+import warning from 'warning';
 
 function calcPoints(vertical, marks, dots, step, min, max) {
+  warning(dots ? step : true, '`Slider[step]` should be a positive number in order to make Slider[dots] work.');
   const points = Object.keys(marks).map(parseFloat);
   if (dots) {
     for (let i = min; i <= max; i = i + step) {