Using lodash in JavaScript to flatten a nested object structure

Question

Using lodash in JavaScript to flatten a nested object structure

I'm looking to flatten a hierarchical json structure. Here is an example of my json data:

{
  "id": "111",
  "name": "v5",
  "define": {
    "system": "abc",
    "concept": [{
      "code": "y7",
      "concept": [{
        "code": "AGG",
        "display": "Abcess"
      }, {
        "code": "ABS",
        "display": "Abcess"
      }]
    }, {
      "code": "y8",
      "concept": [{
        "code": "AGc",
        "display": "ccc"
      }, {
        "code": "hjj",
        "display": "uii"
      }]
    }]
  }
}

Is there a way using lodash to flatten this json and extract only the "code, display" pairs into an array?

If not, are there any other libraries that can achieve this? Thank you.

For example, the desired output would look like this:

[{
  "code": "AGG",
  "display": "Abcess"
}, {
  "code": "ABS",
  "display": "Abcess"
}, {
  "code": "AGc",
  "display": "ccc"
}, {
  "code": "hjj",
  "display": "uii"
}]

javascript angularjs json node.js lodash

Answer 1

Answer №1

This code snippet utilizes the Array#forEach() method to provide a solution.

var data = { "id": "111", "name": "v5", "define": { "system": "abc", "concept": [{ "code": "y7", "concept": [{ "code": "AGG", "display": "Abcess" }, { "code": "ABS", "display": "Abcess" }] }, { "code": "y8", "concept": [{ "code": "AGc", "display": "ccc" }, { "code": "hjj", "display": "uii" }] }] } },
    flat = function (array) {
        var r = [];
        array.forEach(function (a) {
            a.concept.forEach(function (b) {
                r.push(b);
            });
        });
        return r;
    }(data.define.concept);

document.write('<pre>' + JSON.stringify(flat, 0, 4) + '</pre>');

Answer 2

This code snippet utilizes the Array#forEach() method to provide a solution.

var data = { "id": "111", "name": "v5", "define": { "system": "abc", "concept": [{ "code": "y7", "concept": [{ "code": "AGG", "display": "Abcess" }, { "code": "ABS", "display": "Abcess" }] }, { "code": "y8", "concept": [{ "code": "AGc", "display": "ccc" }, { "code": "hjj", "display": "uii" }] }] } },
    flat = function (array) {
        var r = [];
        array.forEach(function (a) {
            a.concept.forEach(function (b) {
                r.push(b);
            });
        });
        return r;
    }(data.define.concept);

document.write('<pre>' + JSON.stringify(flat, 0, 4) + '</pre>');

Answer 3

Answer №2

How can I use lodash to transform this JSON into an array of "code, display" pairs only?

Are you asking if we should combine all the children under the `concept` key?

Here is a suggested solution:

var obj = {
  "id": "111",
  "name": "v5",
  "define": {
    "system": "abc",
    "concept": [{
      "code": "y7",
      "concept": [{
        "code": "AGG",
        "display": "Abcess"
      }, {
        "code": "ABS",
        "display": "Abcess"
      }]
    }, {
      "code": "y8",
      "concept": [{
        "code": "AGc",
        "display": "ccc"
      }, {
        "code": "hjj",
        "display": "uii"
      }]
    }]
  }
}

var output = [];

obj.define.concept.forEach(function(o) {
  output = output.concat(o.concept)
});

document.write("<pre>" + JSON.stringify(output, 0, 4) + "</pre>");

Answer 4

How can I use lodash to transform this JSON into an array of "code, display" pairs only?

Are you asking if we should combine all the children under the `concept` key?

Here is a suggested solution:

var obj = {
  "id": "111",
  "name": "v5",
  "define": {
    "system": "abc",
    "concept": [{
      "code": "y7",
      "concept": [{
        "code": "AGG",
        "display": "Abcess"
      }, {
        "code": "ABS",
        "display": "Abcess"
      }]
    }, {
      "code": "y8",
      "concept": [{
        "code": "AGc",
        "display": "ccc"
      }, {
        "code": "hjj",
        "display": "uii"
      }]
    }]
  }
}

var output = [];

obj.define.concept.forEach(function(o) {
  output = output.concat(o.concept)
});

document.write("<pre>" + JSON.stringify(output, 0, 4) + "</pre>");

Using lodash in JavaScript to flatten a nested object structure

Answer №1

Answer №2

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