Why Does `console.log` Show the Final Object State, and How Can I See its Initial State?

Troubleshooting Console.Log Output for Object State

In many browsers, including Safari without add-ons, console.log displays the object's state at the end of execution rather than at the time of the function call. This can lead to confusion when debugging.

Understanding the Issue

When using console.log with an object, it only logs a reference to the object. Since objects are mutable, any changes made to the object after the console.log call will be reflected in the displayed output.

Solution: Using console.dir()

The console.dir() function provides a solution to this issue. It prints a directory of the object's properties at the time the function is called, giving an accurate representation of its state.

Example:

var test = {a: true}
console.dir(test); // {a: true}
test.a = false; 
console.dir(test); // {a: false}

Alternative Solution: JSON String Conversion

Another approach is to convert the object to a JSON string using JSON.stringify(). This string can then be logged using console.log, and then parsed back into an object using JSON.parse(). This method provides similar functionality to console.dir().

Code Example:

console.log(JSON.parse(JSON.stringify(obj)));

By utilizing either console.dir() or the JSON string conversion technique, developers can accurately display the current state of an object when using console.log. This eliminates the issue of stale data and enhances debugging efficiency.

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