How Can I Convert a JavaScript Dot Notation String into an Object Reference?

Converting a JavaScript String in Dot Notation into an Object Reference

Understanding the Need

Given a JavaScript string that represents a property path in an object using dot notation (e.g., "a.b"), the goal is to convert this string into an actual reference to the desired property within the object.

The Evaluation Method

One straightforward method to accomplish this conversion is to use the eval() function. While using eval() is generally discouraged for security reasons, it is applicable in this specific scenario because the input string is controlled and expected to adhere to a specific syntax. The code would simply use eval("obj" string) to obtain the desired property reference.

A String-to-Array-to-Object Conversion

An alternative, less concise but potentially more efficient and robust approach involves converting the dot-notation string into an array of key names (e.g., ["a", "b"]) and subsequently using this array as a reference path:

const keyArray = dotNotationString.split('.');
const value = obj[keyArray[0]][keyArray[1]];

Recursive Function Implementation

A third option is to create a recursive function that navigates the object using the input string:

function getPropertyByDotNotation(obj, string) {
  if (!obj) {
    return undefined;
  }
  if (!string || string.length === 0) {
    return obj;
  }
  const [key, ...rest] = string.split('.');
  return getPropertyByDotNotation(obj[key], rest.join('.'));
}

This recursive approach provides flexibility and handles objects of arbitrary depth.

Conclusion

The choice of method depends on specific requirements and performance considerations. When working with trusted input and targeting simplicity, eval() can be suitable. For scenarios with performance concerns or more complex input validation, the array or recursive approaches offer reliable alternatives.

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