How is it possible for this for loop to function properly without the need to pass the incrementing variable

Question

How is it possible for this for loop to function properly without the need to pass the incrementing variable

I managed to compile my code and it's working fine, but there's something interesting - the variable that should reference the incrementing value is not included as an argument in the for loop.

var _loop2 = function _loop2() {
    var p = document.createElement('p');
    p.setAttribute('class', 'location__result');
    p.setAttribute('data-id', response.features[i].id);
    p.setAttribute('data-center', response.features[i].center);
    p.textContent = response.features[i].place_name;
    p.addEventListener('click', function () {
        endingInput.value = p.textContent;
        endingResults.style.display = "none";
        placeIconAndZoom(p, position);
    });
    endingResults.appendChild(p);
};

for (var i = 0, length = response.features.length; i < length; i++) {
    _loop2();
}

javascript typescript for-loop

Answer 1

Answer №1

When a function (x) is declared within another function (y), it has access to all variables within the scope of function x, unless they are masked by variables with the same name.

The function y can refer to the global or module scope rather than being limited to just a specific function.

var example = "sample";

function x() {
    console.log(example);
}

x();

Answer 2

When a function (x) is declared within another function (y), it has access to all variables within the scope of function x, unless they are masked by variables with the same name.

The function y can refer to the global or module scope rather than being limited to just a specific function.

var example = "sample";

function x() {
    console.log(example);
}

x();

Answer 3

Answer №2

One of the reasons why ES6 introduced const and let was to address issues like this.

The main difference lies in scoping: var has a function-level scope, meaning variables defined with var can be accessed anywhere within that function declaration. On the other hand, const and let have block-level scope.

In your scenario, you declared var i inside a for loop, which belongs to the function scope. This allows you to access i from within the _loop2 function called by the for loop.

If you're still unsure, I recommend reading this comprehensive answer on Stack Overflow: What's the difference between using "let" and "var"?

To resolve this issue, consider adding 'use strict' at the beginning of your script file. Alternatively, it's best practice to use let instead of var (unless necessary) for better code quality.

Answer 4

One of the reasons why ES6 introduced const and let was to address issues like this.

The main difference lies in scoping: var has a function-level scope, meaning variables defined with var can be accessed anywhere within that function declaration. On the other hand, const and let have block-level scope.

In your scenario, you declared var i inside a for loop, which belongs to the function scope. This allows you to access i from within the _loop2 function called by the for loop.

If you're still unsure, I recommend reading this comprehensive answer on Stack Overflow: What's the difference between using "let" and "var"?

To resolve this issue, consider adding 'use strict' at the beginning of your script file. Alternatively, it's best practice to use let instead of var (unless necessary) for better code quality.

How is it possible for this for loop to function properly without the need to pass the incrementing variable

Answer №1

Answer №2

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