增加 yd_array_randomIndices 函数

lib/array/randomIndices.js

@@ -0,0 +1,22 @@
+/**
+ * 数组下表随机排序（洗牌算法）
+ * @author 凌霄云上 <[email protected]>
+ * @category array
+ * @alias yd_array_randomIndices
+ * @param {Array} array
+ * @returns {Array} 返回随机下标数组
+ * @summary 这个函数保持原有数组顺序，根据随机下标数组获取
+ * @example
+ * yd_array_randomIndices(['a','b','c','d','d','e']); 数组下标[0-5]
+ * 结果：可能是[5,3,4,0,1,2]
+ * }
+ */
+
+export default (arr) =>{
+    const indices = Array.from(arr.keys());   
+    for (let i = indices.length - 1; i > 0; i--) {
+        const j = Math.floor(Math.random() * (i + 1));
+        [indices[i], indices[j]] = [indices[j], indices[i]]; 
+    }
+    return indices;
+};