pls explain me this code

Question

im confused with ternary operation
const array = [1,2,1,1,1,4,5]

array.reduce((unique, item ) =>
unique.includes(item)? unique : [...unique, item],[ ])

Answer 1

The reduce function calculates the array with unique elements output.
* It starts by setting an empty array, [ ]
* Use ternary operator to check for whether the iterated item contains in the output array,
* If item contains on output array, return array without modify it, unique
* Else if item does not contain on the output array, unique; then add the item into unique output array using spread operator. [...unique, item]

After the reduce iteration complete, the output array is [1,2,4,5] only contains unique elements.

Answer 2

i want to know in depth does accumulator unigue gets all the array value item while item iterate throught array during function runs

Answer 3

output array is accumulator right

Answer 4

Understand ternary operation just as a simple if-else condition.

(condition to check)? (if condition is true) : (else)

Ex:
x= (2>3)? 2: 3
Since the condition is false so, x will have a value 3.