Automatic number conversion

LRE allows you to automatically convert component values and table data to number when they are numeric by setting lre.autoNum(true) in your system script.

Problem description

The following code used on Let's Role script raises a difficulty :

const bonusStrength = 1;
log('Base strength = ' + sheet.get('strength').value());
log('Total strength = ' + (sheet.get('strength').value() + bonusStrength));
/* log output example
  Base strength = 12
  Total strength = 121
*/

The bonus should be mathematically added to the strength component value but we can see that it is concatenated.

One common way to prevent this problem is to add parseInt() functions or Number API everywhere it is needed. The previous code is fixed as followed

const bonusStrength = 1;
log('Base strength = ' + sheet.get('strength').value());
log('Total strength = ' + (parseInt(sheet.get('strength').value()) + bonusStrength));
/* log output example
  Base strength = 12
  Total strength = 13
*/

This simple solution makes the code a little harder to read and some exhaustive systems have dozens of parseInt in their script. Moreover you can lose time coding and debugging your system because you forgot to add parseInt.

An example of parseInt forest in D&D4 system :

We can notice the same problem with table data. The following code shows that table data are always strings. (notice the double-quotes around the numbers that mean val is a string)

Tables.get('test').each(log);
/*
Log output :
Object { id: "1", val: "42" }
Object { id: "2", val: "2.3" }
Object { id: "3", val: "23E2D" }
*/

LRE solution = lre.autoNum(true)

LRE offers a flag that allows you to automatically have a number value when it is a numeric value (a string containing a number) in the component. This works for integer and decimal numbers. So you don't need to use parseInt, parseFloat or Number anymore. lre.autoNum is set to false by default and can be changed anywhere in your system code. Please note that any code run before lre.autoNum(true) won't have any automatic conversions.

const init = lre(function (sheet) {
  lre.autoNum(true);
  const bonusStrength = 1;
  log('Base strength = ' + sheet.get('strength').value());
  log('Total strength = ' + (sheet.get('strength').value() + bonusStrength));
  /* log output example
    Base strength = 12
    Total strength = 13
  */
};

The flag allows to automatically convert to number the table data as well. The following code from a previous example shows how the data is converted to number when possible. (you can notice in the log output that double-quotes are no more around values of val because they are real numbers and not string anymore ; this happens only when possible as you can see for the third data that keeps being a string)

lre.autoNum(true);
Tables.get('test').each(log);
/*
Log output :
Object { id: 1, val: 42 }
Object { id: 2, val: 2.3 }
Object { id: 3, val: "23E2D" }
*/