javascript - Turning a string, '+' into the + operator -

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• jquery if statement variable mathematical operator [duplicate] 5 answers

hi i'm making string calculator , add. i'm using coffeescript , in code provided finalnum 0, operator '+' , it's iterating through array of integers. plan on adding more operators later , looking simpler way (not massive if else) change string it's corresponding operator. help!

for num in equation_array     finalnum = finalnum operator num 

the simplest way abstract using functions instead of trying abstract on operator directly.

var ops = {   '+': function(a,b){ return + b; },   '-': function(a,b){ return - b; },   '*': function(a,b){ return * b; },   '/': function(a,b){ return / b; } };  var opstr = "+"; final_num = ops[opstr](final_num, num);