Run results for: eval vs new Function vs mathjs vs infix parse

Test name	Executions per second
✓ new Function	29,537,648 Ops/sec
eval	7,952,271 Ops/sec
evaluateExpression	170,868 Ops/sec
mathjs	154,031 Ops/sec
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}`);