I just wanted to know why in my code I have changed cr = 6 in a method, but when printing the original obj cr value, it is not changed to 6, but remains its original value. Why? If instead I use cr.next = 6, then the value gets changed in the original obj. I expect obj.next = 6. The output generated is:
{
val: 1,
next: {
val: 2,
next: {
val: 3,
next: null
}
}
}
I expected the output to be like this:
{
val: 1,
next: 6
}
let obj = {
val: 1,
next: {
val: 2,
next: {
val: 3,
next: null
}
}
}
cr = obj.next;
cr = 6;
console.log(obj)The first part,
cr = obj.next;
Means "The value of the identifier (the word cr) is the value at the location of memory that the object obj.next is"
cr = 6;
Means "Completely disregard any previous value of cr; the value of the identifier cr is now the integer literal 6"
JavaScript, unlike C/C++ (with pointers, or pass-by-reference vs pass-by-value), does not have a way to change the value of an object with a single identifier (variable name). It can change what the value of the variable is, but not the object it was previously pointing to.
let obj = {
val: 1,
next: {
val: 2,
next: {
val: 3,
next: null
}
}
}
cr = obj.next;
cr = 6;
console.log(obj)
console.log("...........................")
obj.next = 6
console.log(obj)
console.log("...........................")
console.log(cr)
cr = obj.next;
cr = 6;When you do cr = obj.next, it makes a new variable and assigns the obj.next value to cr. After that, you assign 6 to cr so it overwrites the current value of cr and there will be only 6.
If you want an answer like {val: 1, next: 6}, you should write obj.next = 6
so you get your desire output.
I hope it helps you "keep coding".