Lodash flatten method
语法：
Recursively flattens array.
参数
array (Array) − The array to flatten.
输出：
(Array) − Returns the new flattened array.
实例：
var _ = require('lodash');
var list = [1, [2], [4], 5, [[6]]];
var result = _.flattenDeep(list)
console.log(result);
Save the above program in
tester.js. Run the following command to execute this program.
命令：
输出：
