How To Get The Path From Javascript Object From Key And Value

I have a javascript object width depth. I need to know the exact path from this key within the object ex: 'obj1.obj2.data1' I already know the key is data1, the value is 123. My ja

Solution 1:

I think recursive function can help to you (Updated version, to check value)

function path(c, name, v, currentPath, t){
    var currentPath = currentPath || "root";

    for(var i in c){
      if(i == name && c[i] == v){
        t = currentPath;
      }
      else if(typeof c[i] == "object"){
        return path(c[i], name, v, currentPath + "." + i);
      }
    }

    return t + "." + name;
};

console.log(path({1: 2, s: 5, 2: {3: {2: {s: 1, p: 2}}}}, "s", 1));

Solution 2:

The following finds the path in any level of nested objects. Also with arrays. It returns all the paths found, which is something you want if you have keys with the same name.

I like this approach because it works with lodash methods get and set out-of-the-box.

function findPathsToKey(options) {
  let results = [];

  (function findKey({
    key,
    obj,
    pathToKey,
  }) {
    const oldPath = `${pathToKey ? pathToKey + "." : ""}`;
    if (obj.hasOwnProperty(key)) {
      results.push(`${oldPath}${key}`);
      return;
    }

    if (obj !== null && typeof obj === "object" && !Array.isArray(obj)) {
      for (const k in obj) {
        if (obj.hasOwnProperty(k)) {
          if (Array.isArray(obj[k])) {
            for (let j = 0; j < obj[k].length; j++) {
              findKey({
                obj: obj[k][j],
                key,
                pathToKey: `${oldPath}${k}[${j}]`,
              });
            }
          }

          if (obj[k] !== null && typeof obj[k] === "object") {
            findKey({
              obj: obj[k],
              key,
              pathToKey: `${oldPath}${k}`,
            });
          }
        }
      }
    }
  })(options);

  return results;
}

findPathsToKey({ obj: objWithDuplicates, key: "d" })
// ["parentKey.arr[0].c.d", "parentKey.arr[1].c.d", "parentKey.arr[2].c.d"]

Try it here - https://jsfiddle.net/spuhb8v7/1/

If you want the result to be a single key (first encountered), you can change the results to be a string and if defined, then return the function with it.

Solution 3:

I ended up with the following function, that works with nested objects/arrays :

function findPath (obj, name, val, currentPath) {
  currentPath = currentPath || ''

  let matchingPath

  if (!obj || typeof obj !== 'object') return

  if (obj[name] === val) return `${currentPath}['${name}']`

  for (const key of Object.keys(obj)) {
    if (key === name && obj[key] === val) {
      matchingPath = currentPath
    } else {
      matchingPath = findPath(obj[key], name, val, `${currentPath}['${key}']`)
    }

    if (matchingPath) break
  }

  return matchingPath
}

const treeData = [{
  id: 1,
  children: [{
    id: 2
  }]
}, {
  id: 3,
  children: [{
    id: 4,
    children: [{
      id: 5
    }]
  }]
}]

console.log(findPath (treeData, 'id', 5))

Solution 4:

JSON Object can be handled in JavaScript as associative array.

So You can cycle through and store indexes of "parents" in some variables.

Assume the whole object to be stored in variable called obj.

for( var p1 in obj )

{

   for( var p2 in obj[ p1 ] )
   {
       for( var p3 in obj[ p1 ][ p2 ] )
       {
           // obj[ p1 ][ p2 ][ p3 ] is current node
           // so for Your example it is obj.obj1.obj2.data1
       }
   }

}

Hope answer was helpful.

Solution 5:

I would do this job as follows;

Object.prototype.paths = function(root = [], result = {}) {
  var ok = Object.keys(this);
  return ok.reduce((res,key) => { var path = root.concat(key);
                                  typeof this[key] === "object" &&
                                         this[key] !== null ? this[key].paths(path,res)
                                                            : res[this[key]] == 0 || res[this[key]] ? res[this[key]].push(path)
                                                                                                    : res[this[key]] = [path];
                                  return res;
                                },result);
};

var myObj = {
    obj1: {
        obj2: {
            data1: 213,
            data2: "1231",
            obj3: {
                data: "milf"
            }
        }
    },
    obj4: {
        description: "toto",
        cougars: "Jodi",
        category: "milf"
    }
},
value = "milf",
milfPath = myObj.paths()[value]; // the value can be set dynamically and if exists it's path will be listed.
console.log(milfPath);

A few words of warning: We should be cautious when playing with the Object prototype. Our modification should have the descriptor enumerable = false or it will list in the for in loops and for instance jQuery will not work. (this is how silly jQuery is, since apparently they are not making a hasOwnProperty check in their for in loops) Some good reads are here and here So we have to add this Object method with Object.defineProperty() to make it enumerable = false;. But for the sake of simplicity and to stay in the scope of the question i haven't included that part in the code.