I have seen a bit of code similar to this demonstration purpose function, somewhere:
function Pract() {
let a = Array, b;
b = 1;
return b;
}
console.log(Pract())
// Output: 1
However, when I remove Array from the a variable it shows an error: // And I know this is because b is not defined, but so does b in let a = Array, b;
function Pract() {
let a = b;
b = 1;
return b;
}
console.log(Pract())
// Output: Error
Thanks in advance.
The code:
let a = Array, b;
Is same as
let a = Array;
let b;
Which is the same as
let a = Array;
let b = undefined;
So in the original code you define a as an array and b as an undefined variable. Then a value of 1 is assigned the the variable b, and the variable is the returned. The variable a is never used.
In your code, when you do
let a = b
You should get "b is not defined" error, since you're saying a should be something that has never been defined.
To simplify the code, you can simply do
function Pract() {
let b = 1
return b;
}
console.log(Pract())
let a = Array, b; declares two variables, a and b, and sets the value of a equal to the Array function (b is left with a value of undefined). There are no issues with this and it doesn't really have anything to do with Array. You could set a to any other value, or not set it at all, like let a, b;
However, let a = b; declares only a and attempts to set its value to the value of b, which has not been defined anywhere. Thus there is a ReferenceError. This would work, though, if you put b = 1 before let a = b;.
let a = Array, b;declares two variablesaandband initializesawith the valueArray.let a = b;declares only one variableaand reads undeclaredb. "what does Array do in this Javascript function?" nothing.