function Sup(){
this.name = "adc";
this.arr = [1,2,3];
}
Sup.prototype.say = function(){
console.log(this.arr)
}
function Sub(){
Sup.call(this)
}
Sub.prototype = Sup.prototype
var c1 = new Sub()
var c2 = new Sub() Sub.prototype and Sup.prototype to the same memory address Sup the prototype method defined in Sub , there will also be Sub.prototype = Object.create (Sup.prototype) upstairs the positive solution
problem is very big, and you want to give Sub. It is equivalent to adding a method to the child but modifying the parent's prototype. If you have another Sub1 , then Sub1 will also have the methods you add, which is certainly not what we expected.
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