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#Fixed math, the universe and everything in between ! Serverless compatible Math-Only JavaScript EVAL ! Introducing math eval - A math only eval that can actually calculate numbers unlike python and javascript lol, and does not require any library
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const evalMath = (str) => { | |
const operatorToFunction = { | |
"+": (a, b) => a + b, | |
"-": (a, b) => a - b, | |
"*": (a, b) => a * b, | |
"/": (a, b) => a / b | |
}; | |
const operationStr = str.replace(/\s/g, ''); | |
const numbers = operationStr.split(/[-+*/]/).map(Number); | |
const operators = operationStr.split(/\d+/).filter(Boolean).filter(operator => operator !== '.'); | |
for (let i = 0; i < operators.length; i++) { | |
const operator = operators[i]; | |
const nextNumber = numbers[i + 1]; | |
if (operator === '*' || operator === '/') { | |
numbers[i] = operatorToFunction[operator](numbers[i], nextNumber); | |
numbers.splice(i + 1, 1); | |
operators.splice(i, 1); | |
i--; | |
} | |
} | |
let result = numbers[0]; | |
for (let i = 0; i < operators.length; i++) { | |
const operator = operators[i]; | |
const nextNumber = numbers[i + 1]; | |
result = operatorToFunction[operator](result, nextNumber); | |
} | |
const numberString = result.toFixed(15); | |
const decimalIndex = numberString.indexOf('.'); | |
let trimmedNumberString = numberString; | |
if (decimalIndex !== -1) { | |
let i = numberString.length - 1; | |
while (numberString[i] === '0' && i > decimalIndex) { | |
i--; | |
} | |
trimmedNumberString = numberString.substring(0, i + 1); | |
if (trimmedNumberString.charAt(trimmedNumberString.length - 1) === '.') trimmedNumberString = trimmedNumberString.slice(0, -1); | |
} | |
const finalResult = parseFloat(trimmedNumberString); | |
// test: (compares itself to eval) | |
const DEBUG = true; | |
if (DEBUG) { | |
const PERFORM_TEST = false; // <<<<< enable this | |
if (!PERFORM_TEST) { | |
console.log(str, '=', finalResult) | |
} else { | |
const ONLY_SHOW_INVALID = false; | |
try { | |
const evalResult = eval(str); | |
const numberString2 = evalResult.toFixed(15); | |
const decimalIndex2 = numberString2.indexOf('.'); | |
let trimmedNumberString2 = numberString2; | |
if (decimalIndex2 !== -1) { | |
let i2 = numberString2.length - 1; | |
while (numberString2[i2] === '0' && i2 > decimalIndex2) { | |
i2--; | |
} | |
trimmedNumberString2 = numberString2.substring(0, i2 + 1); | |
if (trimmedNumberString2.charAt(trimmedNumberString2.length - 1) === '.') trimmedNumberString2 = trimmedNumberString2.slice(0, -1); | |
} | |
const finalEvalResult = parseFloat(trimmedNumberString2); | |
const isValid = finalResult === finalEvalResult; | |
if (ONLY_SHOW_INVALID) { | |
if (!isValid) console.log(str, '=', finalResult, 'Invalid: ' + finalEvalResult) | |
} else { | |
console.log(str, '=', finalResult, "Is Valid?", isValid, isValid ? 'Valid' : 'Invalid: ' + finalEvalResult) | |
} | |
} catch(e) { | |
console.warn("Eval Error:", str, e.message); | |
} | |
} | |
} | |
// you can remove the test (which uses eval to verify itself) ^^ | |
return finalResult; | |
}; | |
let example; | |
example = evalMath('1 + 1'); | |
example = evalMath('4 - 1'); | |
example = evalMath('2 * 5'); | |
example = evalMath('16 / 4'); | |
example = evalMath('1 + 1 + 2'); | |
example = evalMath('4 - 1 - 2'); | |
example = evalMath('15 * 1000 * 2 / 2 * 2'); | |
example = evalMath('1 + 15 * 1000 * 2 / 2 * 2'); | |
example = evalMath('15 * 1000 * 2 / 2 * 2 + 1'); | |
example = evalMath('16 / 4 / 2'); | |
example = evalMath('5 * 5'); | |
example = evalMath('10 / 2'); | |
example = evalMath('3 + 5 * 2'); | |
example = evalMath('3 * 5 + 2'); | |
example = evalMath('10 - 3 * 2 + 5'); | |
example = evalMath('10 - 3 * 2'); | |
example = evalMath('3 * 2 + 5'); | |
example = evalMath('2 * 3 + 5 * 4'); | |
// example = evalMath('2 * (3 + 5)'); // Error | |
// example = evalMath('a + a'); // Error | |
// example = evalMath('b'); // Error | |
example = evalMath('0'); | |
example = evalMath('20'); | |
example = evalMath('-10 + 10'); | |
example = evalMath('-10 + 12'); | |
example = evalMath('10 - 15'); | |
// example = evalMath('1-'); // Error | |
example = evalMath('-1'); | |
example = evalMath('10 / 3'); | |
example = evalMath('1+1+1*2+1+1+1'); | |
example = evalMath('2.5 * 5'); | |
example = evalMath('1.5 + 1.5'); | |
example = evalMath('4.5 - 1.2'); | |
example = evalMath('2.3 * 2.5'); | |
example = evalMath('16.8 / 4.2'); | |
example = evalMath('1.1 + 1.2 + 2.3'); | |
example = evalMath('4.5 - 1.2 - 2.1'); | |
example = evalMath('15.25 * 100.5 * 2.2 / 2.5 * 2.5'); | |
example = evalMath('1.1 + 15.5 * 100.25 * 2.2 / 2.1 * 2.1'); | |
example = evalMath('15.5 * 1000.2 * 2.1 / 2.5 * 2.5 + 1.5'); | |
example = evalMath('16.5 / 4.5 / 2.5'); | |
example = evalMath('5.5 * 5.5'); | |
example = evalMath('10.5 / 2.5'); | |
example = evalMath('3.5 + 5.5 * 2.5'); | |
example = evalMath('3.2 * 5.5 + 2.5'); | |
example = evalMath('10.5 - 3.2 * 2.5 + 5.5'); | |
example = evalMath('10.5 - 3.2 * 2.5'); | |
example = evalMath('3.5 * 2.5 + 5.5'); | |
example = evalMath('2.1 * 3.5 + 5.5 * 4.5'); | |
example = evalMath('2.5 * 5.2'); | |
example = evalMath('0.1'); | |
example = evalMath('20.2'); | |
example = evalMath('-10.5 + 10.5'); | |
example = evalMath('-10.5 + 12.2'); | |
example = evalMath('10.5 - 15.5'); | |
// example = evalMath('1.1-'); // Error | |
example = evalMath('-1.1'); | |
example = evalMath('10.5 / 3.5'); | |
example = evalMath('1.2+1.3+1.5*2.5+1.7+1.8+1.9'); | |
"Finished" |
Best use case:
Best used when setting up build-time math-only evals, for example rate limits, and NOT for user input
Fixes this eval scenario for example:
const RATE_LIMITS = {
"IP": {
// perSecond: 1,
// perMinute: 1,
// perHour: 2,
// perDay: 6,
// perWeek: 8,
// perMonth: 10,
// perYear: 100,
custom: {
"15 * 1000": 1, // allowed up to 1 request per 15 seconds
"30 * 1000": 1, // allowed up to 1 request per 30 seconds
"15000": 1, // allowed up to 1 request per 15 seconds
"2 minutes": 1, // allowed up to 1 request per 2 minutes
"1 minute": 1, // allowed up to 1 request per 1 minutes
"1 second": 1, //
"0.5 years": 1, //
"0.5 seconds": 1, //
"1 hour and 30 minutes": 1, //
"90 minutes": 1, //
}
},
"Email": {
perSecond: 1,
perMinute: 1,
perHour: 2,
perDay: 3,
perWeek: 4,
perMonth: 5,
perYear: 50,
}
};
for (const limit in RATE_LIMITS) {
if (RATE_LIMITS[limit].custom) {
for (const customLimit in RATE_LIMITS[limit].custom) {
if (customLimit.includes('+') || customLimit.includes('*') || customLimit.includes('-') || customLimit.includes('/')) {
const newLimit = eval(customLimit); // simply replace with evalMath
console.log(newLimit, customLimit);
const limitCount = RATE_LIMITS[limit].custom[customLimit];
delete RATE_LIMITS[limit].custom[customLimit];
if (RATE_LIMITS[limit].custom[newLimit]) {
console.warn("Time Limit Already Exist:", newLimit, customLimit, limit);
} else {
RATE_LIMITS[limit].custom[newLimit] = limitCount;
}
}
}
}
}
console.log(RATE_LIMITS); // This simply replaced the 15 * 1000 with 15000 for example
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Important notes:
If you define
operatorToFunction
outside the scope ofexecuteOperation
sometimes you will getcan not access operatorToFunction before initialization
when testing on the devToolsUnless the
.
is filtered, the operators read it as an operatorUnless the result is fixed to 15 decimal points,
3.3-2.1
does not equal 1.2.To prevent the extra zeros after the decimal caused by fixing to 15 decimal points the third loop is needed.
To prevent cases where a
.
is all that remain after removing all zeros the extra slice is needed at the endTo support multiple operations the
...
is needed