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How to sort Javascript array of objects based on mapped keys between objects

I need to write a function that sorts this array based on dialog_node key and previous_sibling keys. The previous_sibling of the next object matches the dialog_node value of the previous object in the array.


export function orderDialogNodes(nodes) {
  // Create a mapping of dialog_node to its corresponding index in the array
  const nodeIndexMap = {};

  nodes.forEach((node, index) => {
    nodeIndexMap[node.dialog_node] = index;
  });

  // Sort the array based on the previous_sibling property
  nodes.sort((a, b) => {
    const indexA = nodeIndexMap[a.previous_sibling];
    const indexB = nodeIndexMap[b.previous_sibling];

    return indexA - indexB;
  });

  return nodes;
}

const inputArray = [
  {
    type: "folder",
    name: "Item 2",
    dialog_node: "node_2_1702794723026",
    previous_sibling: "node_9_1702956631016",
  },
  {
    type: "folder",
    name: "Item 3",
    dialog_node: "node_3_1702794877277",
    previous_sibling: "node_2_1702794723026",
  }, 
  {
    type: "folder",
    name: "Item 1",
    dialog_node: "node_9_1702956631016",
    previous_sibling: "node_7_1702794902054",
  },
];

const orderedArray = orderDialogNodes(inputArray);
console.log(orderedArray);
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2

Answers


  1. 0

    This might work

    function orderDialogNodes(nodes) {
  return [...nodes].sort((a, b) => {
    if (a.previous_sibling === b.dialog_node) {
      return 1
    }
    if (b.previous_sibling === a.dialog_node) {
      return -1
    }
    return 0
  });
}

const inputArray = [
 {
    type: "folder",
    dialog_node: "node_3_1702794877277",
    previous_sibling: "node_2_1702794723026",
  }, {
    type: "folder",
    dialog_node: "node_2_1702794723026",
    previous_sibling: "node_9_1702956631016",
  },
  {
    type: "folder",
    dialog_node: "node_9_1702956631016",
    previous_sibling: "node_7_1702794902054",
  },
];

const orderedArray = orderDialogNodes(inputArray);
console.log(orderedArray);
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  2. 0

    Keeping your original code as much the same as possible, this should do what you’re looking for.

    To explain it a little, when sorting, you want to return which direction you want the object to move. 1/-1 shift is left or right, and 0 keeps the order the same. Taking the difference of the indices is not going to produce the desired sorting effect.

    The !indexA is added in there because you don’t have a node_7_... in your sample data array.

    export function orderDialogNodes(nodes) {
  // Create a mapping of dialog_node to its corresponding index in the array
  const nodeIndexMap = {};

  nodes.forEach((node, index) => {
    nodeIndexMap[node.dialog_node] = index;
  });

  // Sort the array based on the previous_sibling property
  nodes.sort((a, b) => {
    const indexA = nodeIndexMap[a.previous_sibling];
    const indexB = nodeIndexMap[b.previous_sibling];

    if (indexA < indexB) {
      return 1;
    } else if (!indexA || indexA > indexB) {
      return -1;
    }

    return 0;
  });

  return nodes;
}

const inputArray = [
 {
    type: "folder",
    dialog_node: "node_3_1702794877277",
    previous_sibling: "node_2_1702794723026",
  }, {
    type: "folder",
    dialog_node: "node_2_1702794723026",
    previous_sibling: "node_9_1702956631016",
  },
  {
    type: "folder",
    dialog_node: "node_9_1702956631016",
    previous_sibling: "node_7_1702794902054",
  },
];

const orderedArray = orderDialogNodes(inputArray);
console.log(orderedArray);
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