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javascriptreturncurrying

Return statements with currying techniques

While learning with FreeCodeCamp I'm faced with a question about currying.

The solution was this:

function add(x) {
// Add your code below this line
return function(y) {
  return function(z) {
    return x + y + z;
    }
  }
}
add(10)(20)(30);

However, I'm confused as to why the return statements here aren't terminating the execution of the function?

I was under the impression that as soon as you use a return statement, that line would be executed and everything beyond that would be ignored.

Solution

  • It ends only the own function. The returned function isn't called yet.

    function add(x) {
    return function(y) {      // \
        return function(z) {  //  |
            return x + y + z; //  | part of the returned function
        };                    //  |
    };                        // /
}

add(10)(20)(30);