doubts about  Object.prototype.hasOwnProperty.call (obj);  `? 
 the first understanding: it can be understood here that the this of  Object.prototype.hasOwnProperty  is bound to the  obj  object through the call method, and is judged by this function at the same time? 
 the second understanding: but it seems to be that a  obj  object parameter is passed into the call method of  Object.prototype.hasOwnProperty  and runs inside the call method? But in that case, it looks like the  call  method is performing this judgment operation? 
 about  Function.prototype.call.bind (Object.prototype.hasOwnProperty,obj);  doubts? 
 understands the following code in the first way, but in the second way, I seem to understand it. Here, the  this  of the  Function.prototype.call  function is bound to  Object.prototype.hasOwnProperty  through bind, and the parameter  obj  is passed in, because the actual judgment is performed by the call function, while  Object.prototype.hasOwnProperty  provides a running environment. 
 but understand it this way. Then the related operations of objects that inherit the  call  method are done by the  call  method? 
 for example,  Function.prototype.call.bind (Array.prototype.slice)  intercepts the array by the  call  function? 
 then  call,apply  becomes a universal function? 
