var a = {name:"1"}
function fn(obj){
obj.name = "2";
obj = {name:"3"};
}
fn(a);
a.name // "2"
Why is the output 2
var a = {name:"1"}
function fn(obj){
obj.name = "2";
obj = {name:"3"};
}
fn(a);
a.name // "2"
Why is the output 2
var a = {name: "1"} lets the variable a refer to an object in memory {name: "1"} . When fn (obj) is called, the variable obj references {name: "1"} , and then executes obj.name = "2"; modifies the name property of the reference object.
obj = {name: "3"}; lets the variable obj refer to a new object in memory {name: "3"} .
what was said upstairs is not detailed enough.
here refers to arguments . Before assigning obj , obj , that is,
arguments[0]
is always a reference to a . The assignment breaks the reference chain and reassigns a reference to obj , that is, a new object {name:'3'}
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