How can I convert a JavaScript string in dot notation into an object reference?

Convert a JavaScript String in Dot Notation into an Object Reference

In JavaScript, navigating object properties using dot notation is a common and convenient practice. However, there may be situations where you have a string representing a dot-separated hierarchy and need to convert it into an object reference for easy access.

Problem Statement:

Given an object and a string in dot notation, how can you convert the string into an object reference to access the corresponding property?

Example:

Consider the following object:

var obj = { a: { b: '1', c: '2' } }

And a string:

"a.b"

How can you convert "a.b" to retrieve the value associated with obj.a.b?

Solution:

There are several methods to achieve this:

1. Using the eval() Function (NOT RECOMMENDED):

eval("var val = obj." + string);

This solution directly evaluates the string as code and assigns the result to val. However, using eval() is generally discouraged due to security concerns.

2. Using the [] Operator (Indirect Method):

var val = obj[string];

This method uses the square brackets syntax to access the property indirectly. It works when the string is a valid JavaScript identifier (e.g., no spaces or special characters).

3. Using the reduce() Method:

var val = string.split('.').reduce(function(obj, i) { return obj[i]; }, obj);

This solution splits the string by the period (.) character and uses the reduce() method to traverse the object hierarchy, starting from the root object.

4. Using the multiIndex() Function:

var val = multiIndex(obj, string.split('.'));

function multiIndex(obj, is) {
    return is.length ? multiIndex(obj[is[0]],is.slice(1)) : obj
}

This solution recursively traverses the object hierarchy until the desired property is found. It handles both multi-level dot notation and arrays (if needed).

Handling Arrays (Optional):

In case the string contains array indices, you can use the following approach:

var val = string.match(/[^\]\[.]+/g).reduce(function(obj, i) { return obj[i]; }, obj);

Additional Notes:

• Consider performance implications when using recursion or reduce(), especially for large or complex object hierarchies.
• Ensure that the input strings are sanitized to prevent malicious code execution.
• Property keys in JavaScript are always strings, so object references using dot notation are inherently string-based.

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