CODEWITHSUNDEEP
javascripteval
TheRealFakeNews
TheRealFakeNews

Reputation: 8183

Is there an eval() alternative for this expression?

I have a string expression like such: "1+2+3", and it must stay as a string. In other words, looping and casting the digits to perform the operation isn't an option, so my solution is eval("1+2+3"). But eval() is slow and has all these issues associated with it. Is there an alternative to evaluate my string?

Upvotes: 0

Views: 867

Answers (2)

Joe
Joe

Reputation: 82654

This is a silly question:

var reducer = function (a, b) { 
    return +a + +b; 
};

"1+2+3".match(/[+-]?\d+/g).reduce(reducer); // 6

// or addition only
"1+2+3".split(/\D/).reduce(reducer); // 6

Upvotes: 0

salezica
salezica

Reputation: 77089

Evaluating a string is not only slow, it's dangerous. What if, by malicious user intent or error, you end up evaluating code that crashes your program, destroys your data o opens a security hole?

No, you should not eval() the string. You should split it, cast the operands to numbers, and sum them.

You can keep the string around if you like (you said you needed the string), but using the string to actually perform this operation is a Really Bad Idea.

var string = "1+2+3"
var numbers = string.split('+').map(function(x) { return parseInt(x) })
var sum = numbers.reduce(function(total, x) { return total + x }, 0)

Upvotes: 2

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