javascript - Sum timecodes in array, using only reduce

Question

I have got an array with timecodes, it's look like this: ["5:43", "2:33", "3:45", "0:47", "5:21", "6:56", "3:46", "5:25", "3:14", "3:31", "5:59", "3:07", "11:29", "8:57", "5:49", "5:52", "5:50", "9:13", "11:51", "7:58", "4:40", "4:45", "6:46", "7:24", "7:12", "5:23", "3:34", "8:22", "5:17", "3:10", "4:43", "19:43", "0:47", "0:47", "3:14", "3:59", "2:43", "4:17", "6:56", "3:05", "2:06", "1:59", "1:49", "3:36", "7:10", "3:44", "3:44", "4:36", "3:16", "1:10", "6:10", "2:14", "3:44", "5:05", "6:03", "12:39", "1:56", "4:04"]. I need to sum seconds inside an array, by one reduce method.

Var timer gives me the right list of numbers, which I need to sum. For some reason, it doesn't want to sum it by itself. If I make the timer var an array and push things inside - they have no indexes, so I can't reduce them.

time.reduce((sum, cur) => {
  const [mins, secs] = cur.split(':');
  let timer;
  timer = (parseFloat(mins * 60) + parseFloat(secs));
  console.log(timer);
}); 

question from:https://stackoverflow.com/questions/65879058/sum-timecodes-in-array-using-only-reduce

Answer 1

You are almost there but the problem is that you are not returning anything from the reduce callback. The value return from that callback will be used as sum for the next iteration.

const arr = ["5:43", "2:33", "3:45", "0:47", "5:21", "6:56", "3:46", "5:25", "3:14", "3:31", "5:59", "3:07", "11:29", "8:57", "5:49", "5:52", "5:50", "9:13", "11:51", "7:58", "4:40", "4:45", "6:46", "7:24", "7:12", "5:23", "3:34", "8:22", "5:17", "3:10", "4:43", "19:43", "0:47", "0:47", "3:14", "3:59", "2:43", "4:17", "6:56", "3:05", "2:06", "1:59", "1:49", "3:36", "7:10", "3:44", "3:44", "4:36", "3:16", "1:10", "6:10", "2:14", "3:44", "5:05", "6:03", "12:39", "1:56", "4:04"]

const total = arr.reduce((ac, a) => {
  let [min, secs] = a.split(':').map(Number);
  return ac + secs + (min * 60)
}, 0)

console.log(total)