Benchmark: switch literals - MeasureThat.net

Script Preparation code:

var str = 'abcdefghijklmnop';
str = str.charAt(Math.floor(Math.random() * 3));

Tests:

switch
switch (str) { case 'a': console.log('A'); break; case 'b': console.log('B'); break; case 'c': console.log('C'); break; case 'd': console.log('C'); break; case 'e': console.log('d'); break; case 'f': console.log('e'); break; case 'g': console.log('f'); break; case 'h': console.log('g'); break; case 'i': console.log('h'); break; case 'j': console.log('b'); break; case 'l': console.log('c'); break; case 'k': console.log('x'); break; case 'l': console.log('z'); break; case 'm': console.log('w'); break; case 'n': console.log('q'); break; case 'o': console.log('Ce'); break; case 'p': console.log('r'); break; }
literal
var objLiteral = { a: function() { console.log('A'); }, b: function() { console.log('B'); }, c: function() { console.log('C'); }, d: function() { console.log('B'); }, e: function() { console.log('C'); }, f: function() { console.log('B'); }, g: function() { console.log('C'); }, h: function() { console.log('B'); }, i: function() { console.log('C'); }, j: function() { console.log('B'); }, k: function() { console.log('C'); }, l: function() { console.log('C'); }, m: function() { console.log('C'); }, n: function() { console.log('C'); }, o: function() { console.log('C'); }, p: function() { console.log('C'); }, } objLiteral[str]();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
switch
literal

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

The provided JSON represents a JavaScript benchmark test case for the `switch` statement and its usage with literals.

**What is being tested?**

Two main aspects are being tested:

1. **Switch statements**: The first test case, "switch", measures the performance of using a traditional switch statement (also known as a switch expression) in JavaScript.
2. **Literals with switch statements**: The second test case, "literal", specifically tests the use of literals (strings or numbers) in switch statements.

**Options compared**

In both test cases:

*   The same variable `str` is randomly assigned a value from a predefined string 'abcdefghijklmnop' using `Math.floor(Math.random() * 3)`.
*   Both switch statements have the same number of cases: 12.
*   The only difference lies in how the literal values are used:
    *   In "switch", the literals are used directly within the switch statement's expression, i.e., `str` is the value being switched on.
    *   In "literal", a string literal is assigned to an object property using bracket notation (`objLiteral[str]`), effectively creating a lookup table.

**Pros and Cons**

**Switch statements (both cases):**

*   **Pros:**
    *   Traditional switch statement syntax is familiar and easy to understand.
    *   Can be more readable in some situations, especially when dealing with multiple conditions.
*   **Cons:**
    *   May lead to longer execution times due to the overhead of evaluating `switch` expressions.

**Literals with switch statements (both cases):**

*   **Pros:**
    *   Often leads to shorter execution times because literals are directly compared, reducing evaluation overhead.
    *   Can improve readability and maintainability in certain situations.
*   **Cons:**
    *   May require more developer expertise to understand the nuances of literal-based switch statements.

**Library and purpose**

There is no specific library mentioned in the provided benchmark JSON. However, `objLiteral` appears to be an object that stores function references for each case value using bracket notation (`objLiteral[str]`). This approach is a common technique in JavaScript for implementing lookup tables or hash maps.

**Special JS feature or syntax**

The test cases use **switch expressions**, which were introduced in ECMAScript 2018 (ES2018). These are a new way to express switch statements, allowing for more concise code and improved readability. The example `case 'a': console.log('A'); break;` is equivalent to the traditional `switch` statement.

**Alternatives**

Other alternatives for implementing switch-like behavior in JavaScript include:

*   **If-else chains**: Using multiple `if` statements to achieve similar logic.
*   **Object property lookup**: Accessing object properties dynamically using bracket notation or `in` operator.
*   **Regular expressions**: Using regex patterns to match and redirect execution based on certain conditions.

These alternatives may have different performance characteristics, readability, and maintainability trade-offs compared to switch expressions.

Related benchmarks:

switch literals (version: 0)

Comparing performance of: switch vs literal

Created: 7 years ago by: Guest

Jump to the latest result

switch

literal

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):