js檢測dict中是否包含某個key 數組中是否含有某元素

dict

ary.hasOwnProperty(key)

 

https://blog.csdn.net/donggx/article/details/53373497?utm_source=blogxgwz8

 

 

list

https://www.cnblogs.com/zaijin-yang/p/12196811.html

 

array.includes(searcElement[,fromIndex])

此方法判斷數組中是否存在某個值，如果存在返回true，否則返回false

var  arr=[1,2,3,4];

if (arr.includes(3))

     console.log( "存在" );

else

     console.log( "不存在" );