chocolate.js

var assert = require('assert');

/********************************
* We want make a package of goal kilos of chocolate. We have
* inventory of small bars (1 kilos each) and big bars (5 kilos each).
* Return the number of small bars to use, assuming we always
* use big bars before small bars. Return -1 if it can't be done.
*
* See the asserts below for examples of input
* and expected output.
*
* If you have node installed, all you need to do to test
* your code is run: `node chocolate.js`. If you see errors,
* it is because the tests below did not pass. Once the
* tests do pass, you will see a log of `Success!`
*
* YOUR CODE BELOW HERE
********************************/

var bigBars = 5;
var smallBars = 1;

function makeChocolate(small, big, goal) {
  var desired_big = Math.floor(goal/bigBars);
  //console.log('big', desired_big);
  var desired_small = goal - (bigBars*desired_big); //parseInt(goal%bigBars);
  //console.log('small', desired_small);
  if (desired_small <= small && desired_big <= big){
    return desired_small;
  } else {
    return -1;
  }
}

/********************************
* YOUR CODE ABOVE HERE
********************************/

assert.equal(
 makeChocolate(4, 1, 9),
 4
);

assert.equal(
 makeChocolate(4, 1, 10),
 -1
);

assert.equal(
 makeChocolate(4, 1, 7),
 2
);

assert.equal(
 makeChocolate(6, 2, 7),
 2
);

assert.equal(
 makeChocolate(4, 1, 5),
 0
);

assert.equal(
 makeChocolate(4, 1, 4),
 4
);

assert.equal(
 makeChocolate(5, 4, 9),
 4
);

assert.equal(
 makeChocolate(9, 3, 18),
 3
);

console.log('Success!');