Enable access to nested properties by utilizing this specific object structure

Question

Enable access to nested properties by utilizing this specific object structure

Looking for a "whitelist" object with the following structure:

{
    a: {
        b: {
            c: ''
        }
    }
}

Trying to apply this object to the following:

{
    a: {
        b: {
            c: 1
        },
        d: 2,
        e: 3
    }
}

The expected result should be:

{
    a: {
        b: {
            c: 1
        }
    }
}

Any suggestions on how to implement this using underscore? I tried using _.pick but had issues with the nested properties.

javascript json underscore.js lodash

Answer 1

Answer №1

Utilizing recursion in conjunction with Array.prototype.reduce():

function retrievePaths(obj, whiteList) {  
  return Object.keys(whiteList)
    .reduce(function(whiteObj, key) {
      if (!obj.hasOwnProperty(key)) {
      } else if(typeof obj[key] === 'object') {
        whiteObj[key] = retrievePaths(obj[key], whiteList[key]);
      } else {
        whiteObj[key] = obj[key];
      }
    
      return whiteObj;
    }, {})
}

var whiteList = {
  a: {
    b: {
      c: ''
    }
  },
  g: ''
};

var obj = {
  a: {
    b: {
      c: 1
    },
    d: 2,
    e: 3
  }
};

var result = retrievePaths(obj, whiteList);

console.log(result);

Answer 2

Utilizing recursion in conjunction with Array.prototype.reduce():

function retrievePaths(obj, whiteList) {  
  return Object.keys(whiteList)
    .reduce(function(whiteObj, key) {
      if (!obj.hasOwnProperty(key)) {
      } else if(typeof obj[key] === 'object') {
        whiteObj[key] = retrievePaths(obj[key], whiteList[key]);
      } else {
        whiteObj[key] = obj[key];
      }
    
      return whiteObj;
    }, {})
}

var whiteList = {
  a: {
    b: {
      c: ''
    }
  },
  g: ''
};

var obj = {
  a: {
    b: {
      c: 1
    },
    d: 2,
    e: 3
  }
};

var result = retrievePaths(obj, whiteList);

console.log(result);

Answer 3

Answer №2

In my approach, I create a function that filters nested properties in an object:

function filterObjectProperties(whitelist, obj) {
    if (_.contains(['boolean', 'number', 'string'], typeof obj))
        return obj;
    var filteredObj = {};
    _.each(whitelist, function(value, propName) {
        var originalValue = obj[propName];
        if (originalValue !== undefined)
            filteredObj[propName] = filterObjectProperties(
                value, originalValue);
    });
    return filteredObj;
}

To use this function, pass your whitelist object as whitelist and the target object as obj.

Answer 4

In my approach, I create a function that filters nested properties in an object:

function filterObjectProperties(whitelist, obj) {
    if (_.contains(['boolean', 'number', 'string'], typeof obj))
        return obj;
    var filteredObj = {};
    _.each(whitelist, function(value, propName) {
        var originalValue = obj[propName];
        if (originalValue !== undefined)
            filteredObj[propName] = filterObjectProperties(
                value, originalValue);
    });
    return filteredObj;
}

To use this function, pass your whitelist object as whitelist and the target object as obj.

Answer 5

Answer №3

To avoid creating a custom function, an alternative approach is to utilize the built-in object methods provided by JavaScript like JSON.stringify and JSON.parse. JSON.stringify takes up to three arguments (value, replacer?, space?). The replacer parameter can either be a customized node visitor function or an array that specifies the property keys to include. With this in mind, the following code snippet demonstrates how you can achieve your desired outcome:

var obj= {
    a: {
        b: {
            c: 1
        },
        d: 2,
        e: 3
    }
};
var tempstr=JSON.stringify(obj.a,['b']);
var newobj=JSON.parse(tempstr);
obj.a=newobj;

After running the above code, accessing 'obj' should now return the whitelisted object as specified.

Answer 6

To avoid creating a custom function, an alternative approach is to utilize the built-in object methods provided by JavaScript like JSON.stringify and JSON.parse. JSON.stringify takes up to three arguments (value, replacer?, space?). The replacer parameter can either be a customized node visitor function or an array that specifies the property keys to include. With this in mind, the following code snippet demonstrates how you can achieve your desired outcome:

var obj= {
    a: {
        b: {
            c: 1
        },
        d: 2,
        e: 3
    }
};
var tempstr=JSON.stringify(obj.a,['b']);
var newobj=JSON.parse(tempstr);
obj.a=newobj;

After running the above code, accessing 'obj' should now return the whitelisted object as specified.

Enable access to nested properties by utilizing this specific object structure

Answer №1

Answer №2

Answer №3

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