How can I retrieve the path to a specific subnode using Javascript/JSON?

Question

How can I retrieve the path to a specific subnode using Javascript/JSON?

What is the best way to obtain a JSON path that leads to a specific child node within an object?

For example:

var data = {
    key1: {
        children: {
            key2:'value',
            key3:'value',
            key4: { ... }
        }, 
    key5: 'value'
}

Assuming we have a variable referencing key4, how can we find the absolute path to access it?

data.key1.children.key4

Is there a method in JavaScript that accomplishes this task?

Appreciate any insights on this matter.

javascript json xpath

Answer 1

Answer №1

Imagine you have a variable containing the string value "key3" and you're wondering how to dynamically access a property based on this string's value.

var str = "key3";
data["key1"]["children"][str];

UPDATE

Unbelievably, I managed to solve it on my first attempt. There may be some glitches, but it successfully works for your scenario

VIEW LIVE DEMO

var x = data.key1.children.key4;

var path = "data";
function search(path, obj, target) {
    for (var k in obj) {
        if (obj.hasOwnProperty(k))
            if (obj[k] === target)
                return path + "['" + k + "']"
            else if (typeof obj[k] === "object") {
                var result = search(path + "['" + k + "']", obj[k], target);
                if (result)
                    return result;
            }
    }
    return false;
}

var path = search(path, data, x);
console.log(path); //data['key1']['children']['key4']

Answer 2

Imagine you have a variable containing the string value "key3" and you're wondering how to dynamically access a property based on this string's value.

var str = "key3";
data["key1"]["children"][str];

UPDATE

Unbelievably, I managed to solve it on my first attempt. There may be some glitches, but it successfully works for your scenario

VIEW LIVE DEMO

var x = data.key1.children.key4;

var path = "data";
function search(path, obj, target) {
    for (var k in obj) {
        if (obj.hasOwnProperty(k))
            if (obj[k] === target)
                return path + "['" + k + "']"
            else if (typeof obj[k] === "object") {
                var result = search(path + "['" + k + "']", obj[k], target);
                if (result)
                    return result;
            }
    }
    return false;
}

var path = search(path, data, x);
console.log(path); //data['key1']['children']['key4']

Answer 3

Answer №2

This is my approach to achieving this task.

/**
 * Function that converts a string path into a value existing in a JSON object.
 * 
 * @param {Object} jsonData The JSON data used for searching the value.
 * @param {Object} path The path used to locate the value.
 * @returns {valueOfThePath|null}
 */
function convertJsonPathToValue(jsonData, path) {
    if (!(jsonData instanceof Object) || typeof(path) === "undefined") {
        throw "Invalid arguments: jsonData: " + jsonData + ", path: " + path;
    }
    path = path.replace(/\[(\w+)\]/g, '.$1'); // Convert indexes to properties
    path = path.replace(/^\./, ''); // Remove leading dot
    var pathArray = path.split('.');
    for (var i = 0, n = pathArray.length; i < n; ++i) {
        var key = pathArray[i];
        if (key in jsonData) {
            if (jsonData[key] !== null) {
                jsonData = jsonData[key];
            } else {
                return null;
            }
        } else {
            return key;
        }
    }
    return jsonData;
}

For testing purposes,

var obj = {d1:{d2:"a",d3:{d4:"b",d5:{d6:"c"}}}};
convertJsonPathToValue(obj, "d1.d2"); // Returns: a 
convertJsonPathToValue(obj, "d1.d3"); // Returns: {d4: "b", d5: Object}
convertJsonPathToValue(obj, "d1.d3.d4"); // Returns: b
convertJsonPathToValue(obj, "d1.d3.d5"); // Returns: {d6: "c"}
convertJsonPathToValue(obj, "d1.d3.d5.d6"); // Returns: c

I hope this solution proves helpful to someone.

Answer 4

This is my approach to achieving this task.

/**
 * Function that converts a string path into a value existing in a JSON object.
 * 
 * @param {Object} jsonData The JSON data used for searching the value.
 * @param {Object} path The path used to locate the value.
 * @returns {valueOfThePath|null}
 */
function convertJsonPathToValue(jsonData, path) {
    if (!(jsonData instanceof Object) || typeof(path) === "undefined") {
        throw "Invalid arguments: jsonData: " + jsonData + ", path: " + path;
    }
    path = path.replace(/\[(\w+)\]/g, '.$1'); // Convert indexes to properties
    path = path.replace(/^\./, ''); // Remove leading dot
    var pathArray = path.split('.');
    for (var i = 0, n = pathArray.length; i < n; ++i) {
        var key = pathArray[i];
        if (key in jsonData) {
            if (jsonData[key] !== null) {
                jsonData = jsonData[key];
            } else {
                return null;
            }
        } else {
            return key;
        }
    }
    return jsonData;
}

For testing purposes,

var obj = {d1:{d2:"a",d3:{d4:"b",d5:{d6:"c"}}}};
convertJsonPathToValue(obj, "d1.d2"); // Returns: a 
convertJsonPathToValue(obj, "d1.d3"); // Returns: {d4: "b", d5: Object}
convertJsonPathToValue(obj, "d1.d3.d4"); // Returns: b
convertJsonPathToValue(obj, "d1.d3.d5"); // Returns: {d6: "c"}
convertJsonPathToValue(obj, "d1.d3.d5.d6"); // Returns: c

I hope this solution proves helpful to someone.

Answer 5

Answer №3

Here is my approach:

I implemented a depth-first search algorithm using a given reference.
The solution utilizes recursion to navigate through the data structure.
This implementation can handle arrays within the object.

(To retrieve the result, you can use the deep_value function.)

var key4Ref = { abc: 123 }

var data = {
    key1: {
        children: {
            key2:'value',
            key3:'value',
            key4: key4Ref
        }, 
        key5: 'value'
    }
}

// Function to find the path to a specific reference within an object.
const pathTo = (ref, data, path = []) => {
  const found = data && Object.entries(data).find(([k,v]) => {
    if (v === ref) return path.push(k)
    if (typeof v === 'object') {
      const tmp = pathTo(ref, v, [...path, k])
      if (tmp) return path = tmp
    }
  })
  if (found) return path
}

console.log(pathTo(key4Ref, data).join('.'))

Answer 6

Here is my approach:

I implemented a depth-first search algorithm using a given reference.
The solution utilizes recursion to navigate through the data structure.
This implementation can handle arrays within the object.

(To retrieve the result, you can use the deep_value function.)

var key4Ref = { abc: 123 }

var data = {
    key1: {
        children: {
            key2:'value',
            key3:'value',
            key4: key4Ref
        }, 
        key5: 'value'
    }
}

// Function to find the path to a specific reference within an object.
const pathTo = (ref, data, path = []) => {
  const found = data && Object.entries(data).find(([k,v]) => {
    if (v === ref) return path.push(k)
    if (typeof v === 'object') {
      const tmp = pathTo(ref, v, [...path, k])
      if (tmp) return path = tmp
    }
  })
  if (found) return path
}

console.log(pathTo(key4Ref, data).join('.'))

Answer 7

Answer №4

var data = {
  // Your data is here
  a: {
    b: {
      c: {
        d: "Assalamu alal muslimin"
      }
    }
  },
  // Your function is here
  take: function(path) {
    var temp = this; // make a copy of the object
    if(!path) return temp; 
    path = path.split("/");
    for(var p in path) {
      if(!path[p]) continue; 
      temp = temp[path[p]]; 
      if(!temp) return temp; 
    }
    return temp;
  }
};

<input placeholder="Please enter the path"/>
<button onclick="document.querySelector('div').innerText = JSON.stringify(data.take(document.querySelector('input').value))">
  Try it
</button>
<br><br>
Data: {a:{b:{c:{d:"Assalamu alal muslimin"}}}}
<br><br>
Code: data.take(path)
<br><br>
Result:
<div></div>

Simply put, the function can be summarized as:

function getDataByPath(data, path) {
    if(!path) return data; 
    path = path.split("/");
    for(var p in path) {
        if(!path[p]) continue; 
        . data = data[path[p]]; 
        if(!data) return data; 
    }
    return data;
}

There is also a shorter version of the function, but it may produce errors if an incorrect path is entered:

function getDataByPath(data, path) {
  for(var i in path.split("/")) data = data[path[i]];
  return data;
}

Answer 8

var data = {
  // Your data is here
  a: {
    b: {
      c: {
        d: "Assalamu alal muslimin"
      }
    }
  },
  // Your function is here
  take: function(path) {
    var temp = this; // make a copy of the object
    if(!path) return temp; 
    path = path.split("/");
    for(var p in path) {
      if(!path[p]) continue; 
      temp = temp[path[p]]; 
      if(!temp) return temp; 
    }
    return temp;
  }
};

<input placeholder="Please enter the path"/>
<button onclick="document.querySelector('div').innerText = JSON.stringify(data.take(document.querySelector('input').value))">
  Try it
</button>
<br><br>
Data: {a:{b:{c:{d:"Assalamu alal muslimin"}}}}
<br><br>
Code: data.take(path)
<br><br>
Result:
<div></div>

Simply put, the function can be summarized as:

function getDataByPath(data, path) {
    if(!path) return data; 
    path = path.split("/");
    for(var p in path) {
        if(!path[p]) continue; 
        . data = data[path[p]]; 
        if(!data) return data; 
    }
    return data;
}

There is also a shorter version of the function, but it may produce errors if an incorrect path is entered:

function getDataByPath(data, path) {
  for(var i in path.split("/")) data = data[path[i]];
  return data;
}

Answer 9

Answer №5

let x;
try{
  x = JSON.parse(prompt("Enter your JSON data"))
}
catch(e) {
   alert("Invalid JSON input")
}
var res = {};
var constructResultCurry = function(src){ return constructResult(res,src); }
        
function constructResult(target, src) {
  if(!src) return;
  target[src.key] = src.val;
}
        
function buildPath(key, obj, overAllKey) {
  overAllKey += (overAllKey ? "." : "") + key;
  if(typeof obj[key] != "object") return { key : overAllKey, val : obj[key] };
  Object.keys(obj[key]).forEach(function(keyInner) {
     constructResultCurry(buildPath(keyInner, obj[key], overAllKey));  
  });
}
        
Object.keys(x).forEach(function(k){
  constructResultCurry(buildPath(k, x, ""));
});
console.log("**************ALL FIELDS****************")
console.log(res);
console.log("******************************************")

let conf = confirm("Do you want to extract a specific field from the JSON?");
if ( conf )
{
   let field = prompt("Enter the field name")
   let results = Object.fromEntries(
  Object.entries(res).filter(([key]) => (key.toLowerCase()).includes((field.toLowerCase()))))
  prompt("Copy to clipboard: Ctrl+C, Enter", JSON.stringify(results));
   console.log(results)
   
} 
else {
   prompt("Copy to clipboard: Ctrl+C, Enter", JSON.stringify(res));
}

This method provides the complete JSON structure along with the path to each field within it. It also allows for the extraction of a specific field based on user request.

Answer 10

let x;
try{
  x = JSON.parse(prompt("Enter your JSON data"))
}
catch(e) {
   alert("Invalid JSON input")
}
var res = {};
var constructResultCurry = function(src){ return constructResult(res,src); }
        
function constructResult(target, src) {
  if(!src) return;
  target[src.key] = src.val;
}
        
function buildPath(key, obj, overAllKey) {
  overAllKey += (overAllKey ? "." : "") + key;
  if(typeof obj[key] != "object") return { key : overAllKey, val : obj[key] };
  Object.keys(obj[key]).forEach(function(keyInner) {
     constructResultCurry(buildPath(keyInner, obj[key], overAllKey));  
  });
}
        
Object.keys(x).forEach(function(k){
  constructResultCurry(buildPath(k, x, ""));
});
console.log("**************ALL FIELDS****************")
console.log(res);
console.log("******************************************")

let conf = confirm("Do you want to extract a specific field from the JSON?");
if ( conf )
{
   let field = prompt("Enter the field name")
   let results = Object.fromEntries(
  Object.entries(res).filter(([key]) => (key.toLowerCase()).includes((field.toLowerCase()))))
  prompt("Copy to clipboard: Ctrl+C, Enter", JSON.stringify(results));
   console.log(results)
   
} 
else {
   prompt("Copy to clipboard: Ctrl+C, Enter", JSON.stringify(res));
}

This method provides the complete JSON structure along with the path to each field within it. It also allows for the extraction of a specific field based on user request.

Answer 11

Answer №6

I am currently working on resolving a problem that involves JSON paths with arrays, and I have devised the following method to tackle it:

function findValuePath(obj, value) {
    // Initialize arrays for results and paths
    let result = [];
    let path = [];

    // Recursive function to search for values
    function searchValue(obj, value) {
        for (let key in obj) {
            // Log the path if the current attribute value matches the target value
            if (obj[key] === value) {
                path.push((Array.isArray(obj) ? `[${key}]` : `.${key}`));
                result = path.slice();
                path.pop();
            }
            // Recursively search if the property is an object or array
            else if (typeof obj[key] === 'object') {
                path.push((Array.isArray(obj) ? `[${key}]` : `.${key}`));
                searchValue(obj[key], value);
                path.pop();
            }
        }
    }

    // Call the recursive function
    searchValue(obj, value);

    // Return the path string if the target value is found, otherwise return an empty string
    return result.length > 0 ? result.join('') : '';
}

Here is an example test case that I created:

let obj = {
    a:1,
    b:"hello",
    c:{
        a:"target000",
        b:"tar",
        c:"target_w",
        d:[
            "target0",
            "target1",
            "target2",
            {
                a:2,
                b:"target"
            }
        ]
    }
}
let res = findValuePath(obj,"target")
console.log(res)                   // ".c.d[3].b"
console.log(`obj${res}`)           // "obj.c.d[3].b"
console.log(eval(`obj${res}`))     // "target"

Answer 12

I am currently working on resolving a problem that involves JSON paths with arrays, and I have devised the following method to tackle it:

function findValuePath(obj, value) {
    // Initialize arrays for results and paths
    let result = [];
    let path = [];

    // Recursive function to search for values
    function searchValue(obj, value) {
        for (let key in obj) {
            // Log the path if the current attribute value matches the target value
            if (obj[key] === value) {
                path.push((Array.isArray(obj) ? `[${key}]` : `.${key}`));
                result = path.slice();
                path.pop();
            }
            // Recursively search if the property is an object or array
            else if (typeof obj[key] === 'object') {
                path.push((Array.isArray(obj) ? `[${key}]` : `.${key}`));
                searchValue(obj[key], value);
                path.pop();
            }
        }
    }

    // Call the recursive function
    searchValue(obj, value);

    // Return the path string if the target value is found, otherwise return an empty string
    return result.length > 0 ? result.join('') : '';
}

Here is an example test case that I created:

let obj = {
    a:1,
    b:"hello",
    c:{
        a:"target000",
        b:"tar",
        c:"target_w",
        d:[
            "target0",
            "target1",
            "target2",
            {
                a:2,
                b:"target"
            }
        ]
    }
}
let res = findValuePath(obj,"target")
console.log(res)                   // ".c.d[3].b"
console.log(`obj${res}`)           // "obj.c.d[3].b"
console.log(eval(`obj${res}`))     // "target"

Answer 13

Answer №7

Adam Rackis' response proved to be quite beneficial in my case. I had to make some minor adjustments to suit my needs, specifically in locating all paths with the value "DOWN".

var jsonData = {
    key1: {
        children: {
            key2: 'value',
            key3: 'value',
            key4: { a: "DOWN" }
        },
        key5: 'DOWN'
    }
};
  
function findPaths(targetPath, targetObject, searchValue) {
  var matchingPaths = [];
  for (var jsonKey in targetObject) {
    if (targetObject.hasOwnProperty(jsonKey)) {
      if (targetObject[jsonKey] === searchValue) {
        matchingPaths.push(targetPath + jsonKey);
      } else if (typeof targetObject[jsonKey] === 'object') {
        var foundPaths = this.findPaths(targetPath +  jsonKey + '.', targetObject[jsonKey], searchValue);
        if (foundPaths.length) {
          matchingPaths = matchingPaths.concat(foundPaths);
        }
      }
    }
  }
  return matchingPaths;
}
  
var resultPaths = findPaths('', jsonData, 'DOWN');
console.log(resultPaths); //["key1.children.key4.a","key1.key5"]

Answer 14

Adam Rackis' response proved to be quite beneficial in my case. I had to make some minor adjustments to suit my needs, specifically in locating all paths with the value "DOWN".

var jsonData = {
    key1: {
        children: {
            key2: 'value',
            key3: 'value',
            key4: { a: "DOWN" }
        },
        key5: 'DOWN'
    }
};
  
function findPaths(targetPath, targetObject, searchValue) {
  var matchingPaths = [];
  for (var jsonKey in targetObject) {
    if (targetObject.hasOwnProperty(jsonKey)) {
      if (targetObject[jsonKey] === searchValue) {
        matchingPaths.push(targetPath + jsonKey);
      } else if (typeof targetObject[jsonKey] === 'object') {
        var foundPaths = this.findPaths(targetPath +  jsonKey + '.', targetObject[jsonKey], searchValue);
        if (foundPaths.length) {
          matchingPaths = matchingPaths.concat(foundPaths);
        }
      }
    }
  }
  return matchingPaths;
}
  
var resultPaths = findPaths('', jsonData, 'DOWN');
console.log(resultPaths); //["key1.children.key4.a","key1.key5"]

How can I retrieve the path to a specific subnode using Javascript/JSON?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

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