Variable does not refresh in cart-summary.js

[tryple]

I use prestashop 1.6.1.24.
I have a variable $ total_saving where I keep the total saved from the cart. I have it added in the file cart-summary.js as:

$('#total_saving').html(formatCurrency(json.total_saving, currencyFormat, currencySign, currencyBlank));

I want its value to be refreshed when modifying the cart but it is not refreshed. It only changes its value if I reload the whole page.

I have tried to change the line:
$('#total_price').html(formatCurrency(json.total_price, currencyFormat, currencySign, currencyBlank));
by:
$('#total_price').html(formatCurrency(json.total_saving, currencyFormat, currencySign, currencyBlank));

to check that the value is being calculated correctly and works perfectly. Refresh the value in the Total section of the cart.

What do I have to do more so that this variable is refreshed in the cart?