Why using const in a for loop does not throw an error-PHP Chinese Network Q&A

Article Topic Learning Download Q&A Programming Dictionary Game Recent Updates

简体中文(ZH-CN) English(EN) 繁体中文(ZH-TW)

Why using const in a for loop does not throw an error

P粉244155277 2023-09-08 16:14:20

354

const todolist= [];
let todolisthtml = '';
     for(let i =0;i<todolist.length;i++){
          const todo = todolist[i];
          const html = <p>`${todo}`</p>;
          todolisthtml += html;
      }

Here, whenever we iterate through the loop, we are reassigning the variable todo, which should cause an error because we declared it using "const", but it works smoothly

P粉244155277

reply all(1)

P粉2773052122023-09-09 13:35:23 1 floor

This is not a task. Just declaration and initialization.

If you write

const todolist= [];
let todolisthtml = '';
const todo;
for(let i =0;i`${todo}`;
    todolisthtml += html;
}

This would be a reallocation and is illegal.

In what you wrote, todo and html go out of scope at the end of the loop block, followed by a new todo and html is created for the next iteration.

As Jaromanda X said, const variables are block scoped. And let.