Simple Position Chooser

This package allows for an easy and simple way to choose multiple positions using a string or an array with the desired rules.

How to use

The way to choose the desired positions is by using any of the rules seperated by a comma in a string or by having the rules in an array. Then you use the generated function with the start position and end position to generate the derised positions.

Rules

(X and Y represent an non negative integer number)

1. * : adds all positions. This is a special rule because it cannot be used with any other rule.

2. X : adds the position X.

3. X-Y : adds all positions between X and Y (X and Y included).

4. -X : adds all positions between 0 and X (same as 0-X)

5. X- : adds all positions between X and the last positions (X included)

6. /X : adds all positions that are multiple of X

7. even -> adds all even positions

8. odd -> adds all odd positions

Notes

1. Any invalid rule will simply be ignored.
2. Any position will only be added once, even if there are more than one rule defining it.
3. 0 is a univerval multiple
4. The list of desired positions is always ordered.

Example: '1,3,7-9' will adds positions 1,3,7,8 and 9.

How to use

var processPositionsString = require('simple-position-chooser').processPositionsString;

//The rule list can be a string or an array
var processor=processPositionsString('1,5,/4,13-17');
//or
var processor=processPositionsString([1,5,'/4','13-17']);

// Note: The end value is excluded
//processor(start,end)

processor(0,30)
//generates [ 0, 1, 4, 5, 8, 12, 13, 14, 15, 16, 17, 20, 24, 28 ]

processor(15,40)
//generates [ 15, 16, 17, 20, 24, 28, 32, 36 ]

Example

// In this example 

var array

var processPositionsString = require('simple-position-chooser').processPositionsString;

//The rule returns all possitions from 0 to 10 and all multiples of 5
var processor=processPositionsString('-10,/5');

//goes trough all the array positions that are between 0 and 10 or are multiple of 5
processor(0,array.length).forEach(function(pos){
    var element=array[pos]
    // code
})