Can someone explain the concept of empty and undefined in arrays to me?
Take a look at my code below:
const arr = []
arr[1]=1
arr[2]=2
arr[3]=3
arr[5]=5
console.log(arr[4])// console: undefined
console.log(arr)// console: [empty, 1,2,3,empty,5]
I am confused about why console.log(arr[4]) returns undefined while index 4 of console.log(arr) is actually empty. Can anyone shed light on this for me?
Thank you in advance for your help.
When trying to access a property that is not present, JavaScript returns the value undefined. This behavior is normal in JavaScript.
However, when you log an entire array, you are not directly accessing a specific property. In this case, the console distinguishes between properties that have no value and those that explicitly have the value of undefined.
The term void is automatically inserted by the console interface of the web browser.
When a value has not been assigned to an element in an array, JavaScript will return undefined when you attempt to access it. Additionally, the way unassigned array elements are interpreted can vary depending on the system handling them.
Check out these examples:
let numbers = new Array(3);
console.log(numbers[0]); //undefined
console.log(numbers); //In some environments - [undefined, undefined, undefined]. In other environments [empty x 3]
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