sum_even_fibonacci.js - Find the sum-total of even Fibonacci numbers

sum_even_fibonacci.js

/**
 * Find the sum-total of even Fibonacci numbers
 *
 * @param max - (integer) that specifies the maximum term to count up to (cannot exceed 4 million)
 *
 * Example:
 * sum_even_fibonacci(2) -> 2
 * sum_even_fibonacci(8) -> 10
 * sum_even_fibonacci(34) -> 44
 */
function sum_even_fibonacci(max) {
  // Ensure max does not exceed 4 million
  var LIMIT = 4000000;
  max = parseInt(max < LIMIT ? max : LIMIT) || 0;

  // Start with intial two Fibonacci terms
  var prev_term = 1;
  var current_term = 2;
  var next_term;

  var total = 0;
  // While current-term is within max
  while (current_term <= max) {
    // If the current_term is even, add it to the total
    if (current_term % 2 == 0) {
      total += current_term;
    }

    // Calculate the next-term's value by adding previous-term to current-term
    next_term = prev_term + current_term;

    // Update previous-term with the current-term's value
    prev_term = current_term;

    // Update current-term with the next-term's value
    current_term = next_term;
  }

  return total;
}

module.exports = sum_even_fibonacci;

sum_even_fibonacci.test.js

var sum_even_fibonacci = require('./sum_even_fibonacci');

test('sum_even_fibonacci(0) should equal 0', () => {
  expect(sum_even_fibonacci(0)).toBe(0);
});
test('sum_even_fibonacci(1) should equal 0', () => {
  expect(sum_even_fibonacci(1)).toBe(0);
});
test('sum_even_fibonacci(2) should equal 2', () => {
  expect(sum_even_fibonacci(2)).toBe(2);
});
test('sum_even_fibonacci(3) should equal 2', () => {
  expect(sum_even_fibonacci(3)).toBe(2);
});
test('sum_even_fibonacci(4) should equal 2', () => {
  expect(sum_even_fibonacci(4)).toBe(2);
});
test('sum_even_fibonacci(5) should equal 2', () => {
  expect(sum_even_fibonacci(5)).toBe(2);
});
test('sum_even_fibonacci(8) should equal 10', () => {
  expect(sum_even_fibonacci(8)).toBe(10);
});
test('sum_even_fibonacci(9) should equal 10', () => {
  expect(sum_even_fibonacci(9)).toBe(10);
});
test('sum_even_fibonacci(10) should equal 10', () => {
  expect(sum_even_fibonacci(10)).toBe(10);
});
test('sum_even_fibonacci(34) should equal 44', () => {
  expect(sum_even_fibonacci(34)).toBe(44);
});
test('sum_even_fibonacci(35) should equal 44', () => {
  expect(sum_even_fibonacci(35)).toBe(44);
});
test('sum_even_fibonacci(36) should equal 44', () => {
  expect(sum_even_fibonacci(36)).toBe(44);
});