#2011 - Final Value of Variable After Performing Operations

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Problem Description

There is a programming language with only four operations and one variable X:

++X and X++ increments the value of the variable X by 1.
--X and X-- decrements the value of the variable X by 1.

Initially, the value of X is 0.

Given an array of strings operations containing a list of operations, return the final value of X after performing all the operations.

Solution

/**
 * @param {string[]} operations
 * @return {number}
 */
var finalValueAfterOperations = function(operations) {
  return operations
    .map(n => n.includes('++') ? 1 : -1)
    .reduce((sum, n) => sum + n, 0);
};