Is it possible to filter consecutive numbers from an array in javascript?

Question

I have arrays like this one below.

[1,2,3, 10, 15, 24,25,26,27]

What I want is to filter out the non consecutive numbers excluding the first number in a series but keeping the last in a series like this below.

[2,3, 25,26,27]

I am new to coding and I'm not sure how to write this code yet but I have mocked up pseudocode, would you check this and see if my logic is on track?

Var startArray = [1,2,3, 10, 15, 24,25,26,27];

Var endArray = [ ];

Loop: while there are numbers left in the start array  
 GET: The first number of the startArray

IF: the first number is 1
 MOVE: to next number in the array

IF: the current number + 1 in the array subtracted by the current number -1 in the array === 2
 PUSH: current number into endArray

ELSE IF: the current number -1 ===1
 PUSH: current number into endArray

END IF

END LOOP

Thank you for your help.

Answer 1

You will just have to loop over everything and simply check, if the current number is one higher than the previous number. If so, push it to your resulting array:

var startArray = [1, 2, 3, 10, 15, 24, 25, 26, 27];
var endArray = [];

for(var i = 0; i < startArray.length; i++) {
  if(startArray[i] - 1 === startArray[i - 1]) {
    endArray.push(startArray[i]);
  }
}

$.writeln(endArray); // => 2, 3, 25, 26, 27