Unraveling the complexities of parsing deeply nested object notation - is there no end in

Question

Unraveling the complexities of parsing deeply nested object notation - is there no end in

I'm currently grappling with the task of converting this object hash:

"food": {
    "healthy": {
        "fruits": ['apples', 'bananas', 'oranges'],
        "vegetables": ['salad', 'onions']
    },
    "unhealthy": {
        "fastFood": ['burgers', 'chicken', 'pizza']
    }
}

into a format like this:

food:healthy:fruits:apples
food:healthy:fruits:bananas
food:healthy:fruits:oranges
food:healthy:vegetables:salad
food:healthy:vegetables:onions
food:unhealthy:fastFood:burgers
food:unhealthy:fastFood:chicken
food:unhealthy:fastFood:pizza

In essence, it involves looping through the object while keeping track of the path and generating the desired output.

However, I'm unsure how to recursively loop until all nested elements are processed.

var path;
var pointer;
function loop(obj) {
    for (var propertyName in obj) {
        path = propertyName;
        pointer = obj[propertyName];

        if (pointer typeof === 'object') {
            loop(pointer);
        } else {
            break;
        }        
    }
};

function parse(object) {
    var collection = [];

};

There are two conflicting issues at play here:

If I use recursive programming, it loses track of properties that have already been parsed.
If I don't use recursion, I can't handle infinite nesting.

Any ideas on how to tackle this challenge would be greatly appreciated.

Best regards

javascript parsing object for-loop infinite-loop

Answer 1

Answer №1

The issue with your recursive function stems from storing the state externally rather than within the function itself. To address this, it is essential to contain the state inside the function so that each iteration can keep track of its own state.

Consider implementing the following structure:

var obj = /* ... the object ... */;
var lines = traverse([], "", obj);

function traverse(lines, prefix, obj) {
    var key, encounteredValue = false;

    // Check if it's an array
    if (Object.prototype.toString.call(obj) === "[object Array]") {
        // Since all values in your example are strings added at the end, follow through with that operation
        for (key = 0; key < obj.length; ++key) {
             lines.push(prefix + ":" + obj[key]);
        }
    }
    else {
        // If it's not an array, it must be an object. Recurse for each property and include the property in the prefix on every line
        for (key in obj) {
            traverse(lines, prefix ? (prefix + ":" + key) : key, obj[key]);
        }
    }

    return lines;
}

This solution is impromptu and untested, but it conveys the concept effectively.

Update: Surprisingly, the solution appears to be effective, as demonstrated by Michael Jasper who kindly provided a live demo (source) which has been slightly adjusted.

Answer 2

The issue with your recursive function stems from storing the state externally rather than within the function itself. To address this, it is essential to contain the state inside the function so that each iteration can keep track of its own state.

Consider implementing the following structure:

var obj = /* ... the object ... */;
var lines = traverse([], "", obj);

function traverse(lines, prefix, obj) {
    var key, encounteredValue = false;

    // Check if it's an array
    if (Object.prototype.toString.call(obj) === "[object Array]") {
        // Since all values in your example are strings added at the end, follow through with that operation
        for (key = 0; key < obj.length; ++key) {
             lines.push(prefix + ":" + obj[key]);
        }
    }
    else {
        // If it's not an array, it must be an object. Recurse for each property and include the property in the prefix on every line
        for (key in obj) {
            traverse(lines, prefix ? (prefix + ":" + key) : key, obj[key]);
        }
    }

    return lines;
}

This solution is impromptu and untested, but it conveys the concept effectively.

Update: Surprisingly, the solution appears to be effective, as demonstrated by Michael Jasper who kindly provided a live demo (source) which has been slightly adjusted.

Unraveling the complexities of parsing deeply nested object notation - is there no end in

Answer №1

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