This package contains functions to get the percentage of resemblance (likeness, similarity) between two strings or two objects.
The algorithm used is actually quite simple : it does a case-insensitive levenshtein distance, and also ignores non-alphanumerical characters (such as spaces, dashes, dots, etc).
Quick jump to examples :
The package contains 3 functions :
var resemblance = require('resemblance');
// this modules has 3 functions :
// resemblance.compareStrings(a, b)
// resemblance.compareObjects(a, b, weights)
// resemblance.getSimilar(obj, set, threshold, weights)// the following two strings are a perfect match
// 100% resemblance :
resemblance.compareStrings('Saint-Étienne', 'SAINT ETIENNE');// 90% resemblance :
resemblance.compareStrings('0123456789', '123456789');// 50% resemblance :
resemblance.compareStrings('abc def', 'abc xyz');// 0% resemblance :
resemblance.compareStrings('Hello World', '');// 100% resemblance :
var a = { name: 'David' };
var b = { name: 'David' };
var weights = { name: 100 };
resemblance.compareObjects(a, b, weights);// 67% resemblance :
resemblance.compareObjects(
{ a: 'a', b: 'b', c: 'c' },
{ a: 'a', b: 'c', c: 'b' },
{ a: 67, b: 33, c: 0 }
);
// a is 100% similar,
// b is 100% different,
// c does not matter (weight = 0)In this example, we would like to find similar address objects. the set parameter can be fetched from a database, for example.
// object to compare
var address = {
num: '17',
way: 'Boulevard Antoine de Saint-Exupéry',
zip: '69009',
city: 'Lyon',
country: 'France'
};
// object set
var addresses = [
{
num: '17',
way: 'BOULEVARD SAINT EXUPERY',
zip: '69009',
city: 'LYON',
country: 'FR',
geoloc: {
lat: 45,
lon: 119
}
},
{
num: '17',
way: 'Rue Antoine de Saint-Exupéry',
zip: '69140',
city: 'Rillieux-la-Pape',
country: 'France'
}
];
// weights of each properties
// note that property names can be deeper than one
// level for example, we could put some weight on
// the 'geoloc.lat' property
var weights = {
num: 20,
way: 35,
zip: 15,
city: 20,
country: 10,
geoloc: 0
};
// get addresses that are more than 50% similar
resemblance.getSimilar(obj, set, weights, 0.5)
// returns :
[
{
resemblance: 0.8283333333333333,
obj: {
num: '17',
way: 'BOULEVARD SAINT EXUPERY',
zip: '69009',
city: 'LYON',
country: 'FR',
geoloc: {
lat: 45,
lon: 119
}
}
},
{
resemblance: 0.6426190476190476,
obj: {
num: '17',
way: 'Rue Antoine de Saint-Exupéry',
zip: '69140',
city: 'Rillieux-la-Pape',
country: 'France'
}
}
]