How can I extract the JSON value as a string?

Question

How can I extract the JSON value as a string?

I have a scenario where I define two objects. The first object, BOB, has properties "name" with a value of "bob" and "height" with a value of 185.

var BOB = {
 "name": "bob",
 "height": 185
};

The second object, PROPS, references the height property from the BOB object.

var PROPS = {
"bob": {
  "height": BOB.height
};

As a result, PROPS.bob.height will be equal to 185. When stringified, the object looks like this:

{"bob": {"height": 185}}

Now, the challenge is to determine the original source code that evaluated to the value 185. Is it possible to extract the string representation of the code that produced that result?

var s = findOutTheSourceCode(PROPS);

// The expected output for s would be
/*
{
"bob": {
  "height": BOB.height
}
*/

javascript json

Answer 1

Answer №1

Typically, no. That data is not usually kept in storage.

However, if the code was integrated into a function and you possess a link to that function and you are utilizing a JS engine with support for this atypical feature, it may be possible to call thatfunction.toString() and then attempt to locate the relevant section of code through methods like pattern matching.

Answer 2

Typically, no. That data is not usually kept in storage.

However, if the code was integrated into a function and you possess a link to that function and you are utilizing a JS engine with support for this atypical feature, it may be possible to call thatfunction.toString() and then attempt to locate the relevant section of code through methods like pattern matching.

Answer 3

Answer №2

This design lacks elegance and practicality.

To answer your question directly, the simple answer is "NO, it's not possible."

However, there is a solution that some may consider unattractive but involves using eval, which is generally discouraged. Here is an example:

var BOB = {
 "name": "bob",
 "height": 185
};

var PROPS_src = '{\n'
    + '  "bob": {\n'
    + '    "height": BOB.height\n'
    + '  }'
    + '}';

eval('var PROPS = '+PROPS_src);

console.log("PROPS_SRC:__________________");
console.log(PROPS_src);
console.log("PROPS:______________________");
console.log(PROPS);

// Output:
// PROPS_SRC:__________________
// {
//   "bob": {
//     "height": BOB.height
//   }}
// PROPS:______________________
// { bob: { height: 185 } }

However, I must stress that this approach is highly discouraged. It is strongly advised to reconsider your data structures and possibly refactor your code to improve traceability of data sources.

Here's a (quick and dirty) alternative:

var people = {
    bob: {
     "name": "bob",
     "height": 185
    }
};

var props = {
  "bob": {
    "someConstant": "Hello World",
    "_height": "height",
  }
};

function getProps(who){
    var out = {};
    Object.keys(props[who]).map(function(k){
        if (k.substring(0,1) == "_") {
            out[k.substring(1)] = people[who][props[who][k]];
        } else {
            out[k] = props[who][k];
        };
    }); 
    return out;
};

console.log("Raw:", props['bob']);
console.log("Calculated:", getProps('bob'));

// Output:
// Raw: { someConstant: 'Hello World', _height: 'height' }
// Calculated: { someConstant: 'Hello World', height: 185 }

Answer 4

This design lacks elegance and practicality.

To answer your question directly, the simple answer is "NO, it's not possible."

However, there is a solution that some may consider unattractive but involves using eval, which is generally discouraged. Here is an example:

var BOB = {
 "name": "bob",
 "height": 185
};

var PROPS_src = '{\n'
    + '  "bob": {\n'
    + '    "height": BOB.height\n'
    + '  }'
    + '}';

eval('var PROPS = '+PROPS_src);

console.log("PROPS_SRC:__________________");
console.log(PROPS_src);
console.log("PROPS:______________________");
console.log(PROPS);

// Output:
// PROPS_SRC:__________________
// {
//   "bob": {
//     "height": BOB.height
//   }}
// PROPS:______________________
// { bob: { height: 185 } }

However, I must stress that this approach is highly discouraged. It is strongly advised to reconsider your data structures and possibly refactor your code to improve traceability of data sources.

Here's a (quick and dirty) alternative:

var people = {
    bob: {
     "name": "bob",
     "height": 185
    }
};

var props = {
  "bob": {
    "someConstant": "Hello World",
    "_height": "height",
  }
};

function getProps(who){
    var out = {};
    Object.keys(props[who]).map(function(k){
        if (k.substring(0,1) == "_") {
            out[k.substring(1)] = people[who][props[who][k]];
        } else {
            out[k] = props[who][k];
        };
    }); 
    return out;
};

console.log("Raw:", props['bob']);
console.log("Calculated:", getProps('bob'));

// Output:
// Raw: { someConstant: 'Hello World', _height: 'height' }
// Calculated: { someConstant: 'Hello World', height: 185 }

How can I extract the JSON value as a string?

Answer №1

Answer №2

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