Adding + to the dictionary in javascript

Question

I want to create a dictionary in javascript like this

var operations=
{  
  first:     function(x) 
             {
                return x[0];
             }
}

How can I add the + operation as key to the dictionary that will point to the + operation in javascript? The same thing was done in python by operator.add . How can do it in Javascript?

var operations=
{  
     +    :     return + operation in javascript //syntax is not valid

     first:     function(x) 
                 {
                    return x[0];
                 }
}

.

Possible duplicate of [Overloading Arithmetic Operators in JavaScript?](http://stackoverflow.com/questions/1634341/overloading-arithmetic-operators-in-javascript) — Loek Janssen, Nov 07 '16 at 06:18
Operators are not functions/objects.. You can not to point to them. — vp_arth, Nov 07 '16 at 06:31
Alternative is to use own implementation on objects or functions like `(...rest) => rest.reduce((a, b) => a + b, 0)` — vp_arth, Nov 07 '16 at 06:33
can u show me how the function will look like, the function to add the items in a list — Meta_Data, Nov 07 '16 at 06:52

score 1 · Accepted Answer · answered Nov 07 '16 at 06:10

1

Use "+"

var operations=
{  
     "+"    :     return + operation in javascript //syntax is not valid

     first:     function(x) 
                 {
                    return x[0];
                 }
}

answered Nov 07 '16 at 06:10

void

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A.T. · Answer 2 · 2016-11-07T07:03:06.617

1

Though question is not very clear, but as per my understanding, use function, like

var data = [1,2,3,4,5,6];

var operations=
{  
     "+"    :    function (x){ return x.reduce(function(p,n,ar,i) { return p+=n }, 0) },

     first:     function(x) 
                 {
                    return x[0];
                 }
} 

console.log("SUM: " + operations["+"](data));

console.log("FIRST: " + operations.first(data))

edited Nov 07 '16 at 07:03

answered Nov 07 '16 at 06:18

A.T.

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i just want to get the + operation in javascript.. The same thing done in python by operator.add ... – Meta_Data Nov 07 '16 at 06:24
'+' operators work in two ways in JS, adding values or concatenation , how will you decide what operation to call – A.T. Nov 07 '16 at 06:27
@A.T.— the [*unary + operator*](http://ecma-international.org/ecma-262/7.0/index.html#sec-unary-operators) also does type conversion to number. ;-) – RobG Nov 07 '16 at 06:55
@Meta_Data check the edited one, to add values in an array – A.T. Nov 07 '16 at 07:03

Adding + to the dictionary in javascript

2 Answers2