JavaScript条件语句不起作用

Question

What's wrong with this JavaScript?

var numPackages == 0;

if (coffeeProducts <= 12) {
  numPackages == 1;
} else if (coffeeProducts % 12 == 0) {
  numPackages == coffeeProducts/12;
} else {
  numPackages == (coffeeProducts/12) + 1;
}

Basically, it needs to calculate the number of boxes/packages necessary to ship an amount of items (12 per box). Is there a better way to do this, perhaps using round()?

Answer 1

== is condition.

= is assignment.

The better way is to use Math.ceil() to round to next integer.

So:

var numPackages = Math.ceil(coffeeProducts/12);

Answer 2

All the others explained your mistake with the comparing operator == and the assigning operator = .

The shortest way to solve it would be

var numPackages = Math.ceil( coffeeProducts / 12 );

Answer 3

Make each statement look like this:

if (coffeeProducts <= 12) {
    numPackages = 1; // just "=", not "=="
}

Answer 4

Single equals (=) for assignment: x = 10

Double equals (==) for comparison: if (x == 10)

Triple equals for special cases where type is important as well as the value.

Change your two numPackages lines to a single equals and you're good to go :)