Dice.js

A JavaScript implementation of the Sørensen–Dice coefficient.

Usage

The dice object has two main methods:

• The coefficient method returns an index of similarity for two strings, between 0 and 1.

    dice.coefficient('rabbit season', 'duck season') = 0.545
  

• The overlap method returns an array indicating which strings are similar in two sets of strings.

    dice.overlap(['kiss', 'the', 'bride'], ['there', 'is', 'no', 'try']) = [1, 0, null]
  

  Another example:

    strings input 1 ->  ['AB', 'CD', 'EF', 'GH', 'IJ']
                          0     1     2      3     4
                          |     |     |      |     |
                        [ 0,    2,   null,  null,  3 ]  -> overlap output
                          |      \                /
                          |       `-.          .-'
                          |          \        /
                          0     1     2      3
    strings input 2 ->  ['AA', 'XY', 'CD', 'IJ']
  

The dice object also has two main properties:

• The multigramLength property, set to 2 by default.

  To compare two strings, the algorithm splits them in sets of multigrams (sequences of 2 characters by default, called bigrams). For each pair of identical multigrams, the Sørensen–Dice coefficient goes up. You can set dice.multigramLength to a higher integer to increase the coefficient's accuracy.

• The matchMinimum property, set to 0.5 by default.

  If two strings have a Sørensen–Dice coefficient higher than 0.5, they are considered similar. You can set dice.matchMinimum to a higher value to make the algorithm less tolerant.