Code Kata Solutions - Sum of Positive

1-for-loop.js

const positiveSum = arr => {
  let runningTotal = 0;
  
  for (let i = 0; i < arr.length; i++) {
    const value = arr[i];
    if (value > 0) {
      runningTotal += value;
    }
  }
  
  return runningTotal;
};

2-for-of-loop.js

const positiveSum = arr => {
  let runningTotal = 0;
  
  for (const value of arr) {
    if (value > 0) {
      runningTotal += value;
    }
  }
  
  return runningTotal;
};

3-single-reduce.js

const positiveSum = arr => (
  arr.reduce((runningTotal, value) => {
    if (value > 0) {
      return runningTotal + value;
    } 
    
    return runningTotal;
  }, 0)
);

4-reduce-and-filter.js

const positiveSum = arr => {
  return arr
    .filter(x => x > 0)
    .reduce((a, c) => a + c, 0);
};

5-lovely-functional.js

const sum = (n1, n2) => n1 + n2;

const isPositive = num => num > 0;

const positiveSum = arr => arr
    .filter(isPositive)
    .reduce(sum, 0);