About the difference between for... In and for... Of and object. Keys()

//for in Traversal array What you get is a subscript But it is not recommended to use for in Traversal array , Because it will also traverse the enumerable attributes customized by the developer for the array object and the enumerable attributes on the prototype chain
//for in Traversing the object yields key It will also traverse the enumerable attributes on the prototype chain ;
//for of Traversing the array leads to value
// for of Can't traverse object If you want to traverse the object, you need to cooperate Obeject.keys() But you can traverse class array objects map set aggregate
Can be combined with instance method entries(), Output the contents and index of the array at the same time ;
Write so much for the time being , Another interview tomorrow , Another day, I will sort out and add code