'menu' was used before it was defined
370
371 const internObject = new Intern(name, id, email, school);
372 teamArray.push(internObject);
373 menu();374
375 });
376'menu' was used before it was defined
353
354 const engineerObject = new Engineer(name, id, email, github);
355 teamArray.push(engineerObject);
356 menu();357
358 });
359'menu' was used before it was defined
335
336 const managerObject = new Manager(name, id, email, officeNumber);
337 teamArray.push(managerObject);
338 menu();339
340 });
341'managerQuery' was used before it was defined
318 .then(({ name }) => {
319
320 documentName = name;
321 managerQuery();322
323 });
324};
Description
It is recommended to use a variable only after it is defined as it might produce errors at runtime.
In JavaScript, prior to ES6, variable and function declarations are hoisted to the top of a scope, so it's possible to use identifiers before their formal declarations in code. This can be confusing and some believe it is best to always declare variables and functions before using them.
In ES6, block-level bindings (let and const) introduce a "temporal dead zone" where a ReferenceError will be thrown with any attempt to access the variable before its declaration.
Bad Practice
alert(a);
var a = 10;
f();
function f() {}
function g() {
return b;
}
var b = 1;
{
alert(c);
let c = 1;
}
Recommended
var a;
a = 10;
alert(a);
function f() {}
f(1);
var b = 1;
function g() {
return b;
}
{
let c;
c++;
}