Benchmark: eval vs new Function vs mathjs vs infix parse

HTML Preparation code:

<script src="https://cdnjs.cloudflare.com/ajax/libs/mathjs/6.6.1/math.min.js"></script>

Script Preparation code:

const supportedOperators = {
    '-': {
        precedence: 1,
        operate: (lhs, rhs) => lhs - rhs,
    },
    '+': {
        precedence: 1,
        operate: (lhs, rhs) => lhs + rhs,
    },
    '/': {
        precedence: 3,
        operate: (lhs, rhs) => lhs / rhs,
    },
    '*': {
        precedence: 4,
        operate: (lhs, rhs) => lhs * rhs,
    },
    '^': {
        precedence: 5,
        operate: (lhs, rhs) => lhs ** rhs,
    },
};

function isOperator(value) {
    return !!supportedOperators[value];
}

function isOperand(value) {
    return !Number.isNaN(+value);
}

function getPrecedence(operator) {
    const supportedOperator = supportedOperators[operator];
    if (!supportedOperator) {
        return -1;
    }
    return supportedOperator.precedence;
}

function evaluateLastOperation(operators, operands) {
    const operator = supportedOperators[operators.pop()];
    const rhs = operands.pop();
    const lhs = operands.pop();
    return operator.operate(+lhs, +rhs);
}

function tokenizeExpression(expr) {
    const currentTokens = [];
    let currentValue = '';

    for (let i = 0; i < expr.length; i += 1) {
        if (expr[i] === ' ') {
            if (currentValue) {
                currentTokens.push(currentValue);
                currentValue = '';
            }
        } else if (expr[i] === ')') {
            if (currentValue) {
                currentTokens.push(currentValue);
                currentValue = '';
            }
            currentTokens.push(')');
        } else if (isOperand(expr[i]) ||
            (expr[i] === '.' && currentValue.indexOf('.') === -1 && expr[i + 1]) ||
            (expr[i] === '-' && currentValue.indexOf('-') === -1 && isOperand(expr[i + 1]))) {
            currentValue += expr[i];
        } else if (expr[i] === '(' || expr[i] === ')' || isOperator(expr[i])) {
            currentTokens.push(expr[i]);
        }
    }
    if (currentValue) {
        currentTokens.push(currentValue);
    }
    return currentTokens;
}


function evaluateExpression(expr) {
    const tokens = tokenizeExpression(expr);
    const operands = [];
    const operators = [];

    tokens.forEach((token) => {
        if (isOperand(token)) {
            operands.push(token);
        } else if (token === '(') {
            operators.push(token);
        } else if (token === ')') {
            let operatorTop = operators[operators.length - 1];
            while (operators.length && operatorTop !== '(') {
                operands.push(evaluateLastOperation(operators, operands));
                operatorTop = operators[operators.length - 1];
            }
            operators.pop();
        } else if (isOperator(token)) {
            let operatorTop = operators[operators.length - 1];
            while (operators.length && operatorTop !== '(' && getPrecedence(token) <= getPrecedence(operatorTop)) {
                operands.push(evaluateLastOperation(operators, operands));
                operatorTop = operators[operators.length - 1];
            }
            operators.push(token);
        }
    });

    while (operators.length) {
        operands.push(evaluateLastOperation(operators, operands));
    }

    return operands[0];
}

var testMathExpression = `142 * ( 2 / 0.9 ) ^ -1.2 * 0.9938 ^ 50`;

var func = new Function(`return ${testMathExpression}`);

Tests:

eval
eval(testMathExpression);
new Function
func();
mathjs
math.evaluate(testMathExpression);
evaluateExpression
evaluateExpression(testMathExpression);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
eval
new Function
mathjs
evaluateExpression

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_2_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 17 on iOS 17.2.1

View result in a separate tab

Test name	Executions per second
eval	7952271.0 Ops/sec
new Function	29537648.0 Ops/sec
mathjs	154031.1 Ops/sec
evaluateExpression	170868.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark measures the performance of different approaches to evaluate mathematical expressions in JavaScript: `eval`, `new Function`, `mathjs` (a library for symbolic computation), and `evaluateExpression` (a custom implementation).

**Tested Options**

1. **`eval(testMathExpression)`**: This method uses the built-in `eval()` function to execute a string as JavaScript code.
2. **`func();`**: This method creates a new anonymous function using `Function` constructor and passes the mathematical expression as a string argument.
3. **`math.evaluate(testMathExpression);`**: This method uses the `evaluate()` function from the `mathjs` library to evaluate the mathematical expression.
4. **`evaluateExpression(testMathExpression);`**: This is a custom implementation that tokenizes the expression, then evaluates it using a stack-based algorithm.

**Pros and Cons of Each Approach**

1. **`eval()`**:
	* Pros: Simple to implement, widely supported.
	* Cons: Vulnerable to code injection attacks, can be slow due to dynamic compilation.
2. **`new Function()`**:
	* Pros: More secure than `eval()`, allows for sandboxing the expression.
	* Cons: Can be slower than `eval()` due to function creation overhead.
3. **`mathjs`**:
	* Pros: Provides a safe and efficient way to evaluate mathematical expressions, supports various input formats.
	* Cons: Requires external library dependency, can be overkill for simple cases.
4. **`evaluateExpression()`**:
	* Pros: Custom implementation that may optimize performance for specific use cases.
	* Cons: Requires more development effort, potentially less readable and maintainable.

**Benchmark Results**

The provided benchmark results show the number of executions per second for each test case on a mobile Safari 17 browser:

| Test Case | Executions Per Second |
| --- | --- |
| `new Function` | 29,537,648 |
| `eval` | 7,952,271 |
| `evaluateExpression` | 1,708,68 |
| `mathjs` | 15,403,11 |

The results suggest that the custom implementation (`evaluateExpression`) is significantly slower than the other approaches. However, it's essential to note that this benchmark may not be representative of all use cases or environments.

**Conclusion**

The choice of evaluation method depends on the specific requirements and constraints of your project. If you need a simple, widely supported solution, `eval()` might be sufficient. For more secure and efficient evaluations, consider using `new Function()` or `mathjs`. The custom implementation (`evaluateExpression`) may not be the best choice for most use cases, but it could provide optimization opportunities for specific scenarios.

Related benchmarks:

eval vs new Function vs mathjs vs infix parse (version: 0)

Comparing performance of: eval vs new Function vs mathjs vs evaluateExpression

Created: one year ago by: Guest

Jump to the latest result

eval

new Function

mathjs

evaluateExpression

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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