4.0.0 • Public • Published


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Install via npm

$ npm install sift-distance

NOTE: The major version of this module tracks the algorithm's version. So, if you want to use SIFT 3, for example, you'd install sift-distance@3.0, for version 3B of the SIFT algorithm sift-distance@3.1, for version 4 sift-distance@4.0 and so on.


This implements the SIFT4 extended version.


SIFT( a, b, [options] )

  • String|Buffer|Array a
  • String|Buffer|Array b
  • Object options
    • Number maxOffset
    • Number maxDistance
    • Function tokenizer
    • Function tokenMatcher
    • Function matchEvaluator
    • Function lengthEvaluator
    • Function transpositionEvaluator


Number maxOffset

The maximum largest common substring offset to be matched against one another. Defaults to 5.

Number maxDistance

Distance at which the algorithm should stop computing the value and just exit (the values are too different anyway).

Function tokenizer( value ) -> String|Array|Buffer

  • Mixed value

Function to transform strings into vectors of tokens.

Function tokenMatcher( token1, token2 ) -> Boolean

  • Mixed token1
  • Mixed token2

Function to determine if two tokens match each other (equal).

Function matchEvaluator( token1, token2 ) -> Number

  • Mixed token1
  • Mixed token2

Function to determine the way a token match should be added to the lcs (largest common substring). For example, a fuzzy match could be implemented.

Function lengthEvaluator( lcs ) -> Number

  • Number lcs: largest common substring length

Function to determine the way the lcs value is added to the lcss. For example, longer continuous substrings could be awarded.

Function transpositionEvaluator( transpositions, lcss ) -> Number

  • Number transpositions: number of transpositions
  • Number lcss: largest common subsequence length

Function to determine the way the number of transpositions affects the final result.


npm i sift-distance

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  • jhermsmeier