Question

I am trying to replace some mathematical operators with variables, so that I can change the operator according to some conditions and then an then use that variable in place of the operator.

For example

var abc = 5;
if (abc<5)
// perform subtraction;
else if(abc==5)
// perform addition;
else if(abc>5)
// perform multiplication

Now what I want is that instead performing the operations based on the value of variable abc
assign the operator it self to some variable and then use the variable in place of the operator, so that I can reduce some code and only one block of code can be used in place of 3 or 5 blocks.
Something like this

var sign;
var result;
if(some condition)
sign = "-";
result = 5 sign 4;

I want to do this mainly in javascript.

Answer 1

You can use eval for this specific case:

var  op = "";
if (abc>5)
    op = "-";
else if(abc==5)
    op = "+";
else
    op = "*";
if (op.length > 0)
    alert(eval("10" + op + "10"));

This will perform “dynanic operation” on two numbers (10 and 10 in this example) based on the value of abc by storing the operator as a string then evaluate it.

Live test case.