JavaScript String Concatenation: Do We Really Need a StringBuilder?

Immutability of JavaScript Strings: Do We Need a "String Builder"?

In JavaScript, strings are immutable, meaning you cannot modify their contents once they are created. The myth that string concatenation is slow also persists, making developers assume the need for a string builder. However, benchmarks prove otherwise.

Benchmarks: Performance of String Manipulation Methods

To debunk the myth, we conducted tests comparing different string concatenation methods, including both using array indexing to avoid array pushing and straight string concatenation. The results showed no significant speed differences between the two methods.

Case 1: Concatenating the Same String Repeatedly

• Using array indexing: This method uses an array for storing string parts and then joins them.
• String concatenation: This method concatenates the strings directly using the plus operator.

Results: Both methods showed comparable performance.

Case 2: Concatenating Random Strings

• Using array indexing: This method uses an array for storing string parts and then joins them.
• String concatenation: This method concatenates the strings directly using the plus operator.

Results: Again, both methods showed similar performance.

Conclusion:

Contrary to popular belief, string concatenation in JavaScript is not slow. Therefore, there is no need for a dedicated string builder in the language.

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