You-Dont-Know-JS
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"this & object prototypes": Chapter 2 Clarification??
I don't know if this makes sense or not. As I was trying to digest this chapter, I got sent down a rabbit hole when the call stack was mentioned in finding the call-site. I modified the example in the chapter to read like this.:
function baz() {
var a = 1;
// call-stack is: baz
// so, our call-site is in the global scope
console.log( "baz" );
console.log(this.a);
bar(); // <-- call-site for `bar`
}
function bar() {
var a = 2;
// call-stack is: baz -> bar
// so, our call-site is in baz
console.log( "bar" );
console.log(this.a);
foo(); // <-- call-site for foo
}
function foo() {
var a = 3;
// call-stack is: baz -> bar -> foo
// so, our call-site is in bar
console.log( "foo" );
console.log(this.a);
}
var a = 0;
baz(); // <-- call-site for baz
console.log(this.a);
I confused this.a with the local var a in each function, thinking that I should see baz, 1, bar, 2, foo 3, 0 which would be the output if I my console.log statements were console.log(a) (printing out the local variables in lexical scope for each function call).
Perhaps, it was just my brain confusing this, but if you think otherwise such that others could likewise get confused here, then my suggestion would be to point this out with a similar example.
Use
<your code here>
to format your code, it will be easier to read. Thanks.
result (Chrome 50.0.2661.94 (64-bit), CentOS7):
baz
0
bar
0
foo
0
0
Which browser did you use?
