Sorting an array as close as to another array as possible

Question

How do I sort an array as close as possible to a target array as possible.

For example:

The array can only contain a maximum of 4 elements:

['javascript', 'html', 'css', 'result'];

But in cases where it isn't, the sorting should be as follows:

['css', 'result', 'html']; sorted to ['html', 'css', 'result'];

['result', 'css', 'javascript']; sorted to ['javascript', 'css', 'result'];

The criteria is to get it as close to ['javascript', 'html', 'css', 'result']; as possible, and where a particular element does not exist, skip it.

My current code seems to do it incorrectly, I've included it below:

function setFiddleTabsArray(updatedFiddleTabs) {
  if (updatedFiddleTabs.length === 4) {
    updatedFiddleTabs = ['javascript', 'html', 'css', 'result'];
  } else {
    const correctFiddleTabsOrder = ['javascript', 'html', 'css', 'result'];
    const fiddleTabsSorter = (a, b) => {
      if (correctFiddleTabsOrder.includes(a)) {
        return -1;
      }
      if (correctFiddleTabsOrder.includes(b)) {
        return 1;
      }
      return 0;
    };
    updatedFiddleTabs.sort(fiddleTabsSorter);
    return updatedFiddleTabs;
  }
  return updatedFiddleTabs;
}

const test1 = setFiddleTabsArray(['css', 'html', 'result']);
console.log(test1);

How do I fix it?

It's hard to make sense from the examples. Why, in the example with the array that includes "result" twice, does the result end up with "html" instead? Why not "javascript"? — Pointy
– Pointy, Commented Apr 1, 2021 at 15:13
Sorry I've fixed it. The criteria is to get it as close to ['javascript', 'html', 'css', 'result']; as possible, and where a particular element does not exist, skip it. — methuselah
– methuselah, Commented Apr 1, 2021 at 15:16

epascarello · Accepted Answer · 2021-04-01 15:16:44Z

4

You are always going to get 1 since it is always in the array. You need to sort based on the index of the match

function setFiddleTabsArray(updatedFiddleTabs) {
  if (updatedFiddleTabs.length === 4) {
    updatedFiddleTabs = ['javascript', 'html', 'css', 'result'];
  } else {
    const correctFiddleTabsOrder = ['javascript', 'html', 'css', 'result'];
    const fiddleTabsSorter = (a, b) => {
      return correctFiddleTabsOrder.indexOf(a) - correctFiddleTabsOrder.indexOf(b);
    };
    updatedFiddleTabs.sort(fiddleTabsSorter);
    return updatedFiddleTabs;
  }
  return updatedFiddleTabs;
}

const test1 = setFiddleTabsArray(['css', 'html', 'result']);
console.log(test1);

answered Apr 1, 2021 at 15:16

epascarello

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1 Comment

methuselah Over a year ago

Thanks this fixes it. I really appreciate it!

simon · Accepted Answer · 2021-04-01 15:22:44Z

1

An alternative is to extract the sort ranking to a separate object and sort with the following logic:

const sortRanking = {
  javascript: 0,
  html: 1,
  css: 2,
  result: 3,
};

const setFiddleTabsArray = (updatedFiddleTabs) =>
  updatedFiddleTabs.sort((a, b) => {
    if (sortRanking[a] > sortRanking[b]) return 1;
    if (sortRanking[a] < sortRanking[b]) return -1;
    return 0;
  });

const test1 = setFiddleTabsArray(["css", "html", "result"]);
console.log(test1);

This makes it very explicit and easy to follow imo

answered Apr 1, 2021 at 15:22

simon

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Comments

Julien Ripet · Accepted Answer · 2021-04-01 15:24:48Z

1

If you are always sure that nothing besides 'javascript', 'html', 'css', 'result' will ever be in the array, I would use the filter function.

function setFiddleTabsArray(updatedFiddleTabs) {
  if (updatedFiddleTabs.length === 4) {
      return ['javascript', 'html', 'css', 'result'];
  } else {
    const correctFiddleTabsOrder = ['javascript', 'html', 'css', 'result'];
    let result = correctFiddleTabsOrder.filter(element => updatedFiddleTabs.includes(element))
    return result;
  }
}

const test1 = setFiddleTabsArray(['css', 'html', 'result']);
console.log(test1);

answered Apr 1, 2021 at 15:24

Julien Ripet

5725 silver badges18 bronze badges

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