# jQuery if statement with variable mathematical operator [duplicate]

So I am looking for something similar to this question python if statement with variable mathematical operator but in jQuery/Javascript

Essentially something like

``````var one = "4";

var two = "6";

var op = "==";

if (one op two) {
//do something
}
``````

is this possible? You could define a lot of binary functions:

``````var operators = {
"==": function(a,b){return a==b;},
"<=": function(a,b){return a<=b;},
">=": function(a,b){return a>=b;},
"<": function(a,b){return a<b;},
">": function(a,b){return a>b;},
…
};

var one = "4",
two = "6",
op = "==";
if (op in operators && operators[op](+one, +two)) {
//do something
}
``````

If you don't want to generate such a large object and have no complex functions, you also might be able to generate them on-the-fly (using a bit of `eval` magic):

``````var validOps = /^([!=<>]=|<|>)\$/,
operators = {};
function check(op, x, y) {
if (arguments.length > 1)
return check(op)(x, y);
if (op in operators)
return operators[op];
if (validOps.test(op))
return operators[op] = new Function("a","b","return a "+op+" b;");
return function(a, b){return false;};
}

if (check("==", 4, 6)) {
// do something
}
`````` If you have an operation (otherwise known as a function) that you'd like to perform on two variables, then you simply need to define it:

``````var operations,
a,
b,
op;
operations = {
'==': function (a, b) {
return a == b;
},
'&&': function (a, b) {
return a && b;
},
'||': function (a, b) {
return a || b;
}
};
a = 4;
b = 6;
op = operations['=='];
if (op(a, b)) {
//do stuff
}
`````` You can use Eval for this

`````` if(eval(one+op+two)){
//do something
}
`````` You can use eval() but it should be a string that could be evaluated to javascript to get the desired results.

Live Demo

``````if (eval(one + op + two)) {
//do something
}
`````` I needed something like this recently and ended up writing a function to parse the operator.

Something like:

``````function checkLogic(one, op, two) {
switch(op) {
case '==':
return one == two;
// etc
}
}
``````