全局变量未在函数内部更新

Question

I spent few hours trying to find the reason why the variable dataset_path which is a global variable is always undefined

var dataset_path ;

function myFunction() {
  offline_data_mainlooper_bitfinex();
  print_bilan();
}
function offline_data_mainlooper_bitfinex(){
    var hours_step_size = 1*2;
    var daily_step_size = 24*2,
    // dataset_path = './quote/bitfinex/from_1480550400to_1512100800_1hquote.json';
    // dataset_path =  ('./quote/bitfinex/from_1480550400to_1512100800quote.json') //thats's 30 min
    dataset_path =  './quote/bitfinex/from_1480550400to_1512100800_15mquote.json'
       //... somecode


}
function print_bilan(){
   var filename = './analysis/test_log.json';
   //... somecode
 console.log('Quote saved! to ' +dataset_path, filename)
}

Answer 1

Because of this:

var daily_step_size = 24*2,
//                        ^
dataset_path =  './quote/bitfinex/from_1480550400to_1512100800_15mquote.json'

That's declaring multiple variables in the local scope of offline_data_mainlooper_bitfinex , not ending the daily_step_size declaration and then doing an assignment to the global variable. Replace the comma by a semicolon (or omit it).

Answer 2

It worked for me when I put a ; instead of a , after

var daily_step_size = 24*2,

I think you are declaring a new var which scope is inside the function. So when you're calling the global one, it's undefined.

Hope it helps