varassert=require('assert');varintersperse=require('..');describe('intersperse',function(){it("should return a new array for empty array",function(){vararr=[];varnewArr=intersperse(arr);assert.deepEqual(newArr,[]);assert.deepEqual(arr,[]);assert.ok(newArr!==arr);});it("should return a new array for single-item array",function(){vararr=[1];varnewArr=intersperse(arr);assert.deepEqual(newArr,[1]);assert.deepEqual(arr,[1]);assert.ok(newArr!==arr);});it("should return a new interspersed array",function(){vararr=[1,2,3];varnewArr=intersperse(arr,'a');assert.deepEqual(newArr,[1,'a',2,'a',3]);assert.deepEqual(arr,[1,2,3]);});});