How Can I Display JavaScript Objects as Strings, Handling Circular References?

Displaying JavaScript Objects as Strings

In JavaScript, it's convenient to display variables as strings using alert(), providing a formatted view of their contents. To achieve the same with objects, several methods are available.

Native JSON.stringify Method

The JSON.stringify() method converts an object to a JSON string. It handles nested objects and is widely supported by browsers:

str = JSON.stringify(obj);
str = JSON.stringify(obj, null, 4); // Indented output (optional)
console.log(str); // Log to console
alert(str); // Display in alert

Reversing the Process

JSON.stringify() can be reversed with JSON.parse():

obj = JSON.parse(str);

Custom JSON.stringify Replacer for Circular References

When dealing with circular references, the following error may occur:

"Uncaught TypeError: Converting circular structure to JSON"

To resolve this, use a custom replacer function with JSON.stringify():

str = JSON.stringify(obj, (key, value) => {
  if (typeof value === "object" && value !== null) {
    return "[Circular]"; // Replace circular references with a placeholder
  }
  return value;
});

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