fuzzy-equal

Fuzzy-Equals

A function to deeply compare values and produce a naive percentage of similarity and other metrics to analyze the difference between them. The notion of equality in this library is defined as exact type, value, and structural equality.

Example

var fuzzyEqual = require('fuzzy-equal');
 
var expectation = {
    a: 1,
    b: 2,
    c: ['a','b','c']
}
 
var reality = {
    a: 1,
    b: null,
    c: ['a','b','f','d']
}
 
var comparison = fuzzyEqual(expectation, reality);
/*
{ matching_types: true,
  property_count: 3,
  matching: 1,
  similarity: 0.3333333333333333,
  deep_equal: false,
  differing_properties: [],
  common_properties: { a: true, b: true, c: true },
  deep_differences:
   { b: { matching_types: false, similarity: 0, deep_equal: false },
     c:
      { matching_types: true,
        property_count: 4,
        matching: 2,
        similarity: 0.5,
        deep_equal: false } },
  left_only: [],
  right_only: [] }
*/

Documentation

The function fuzzyEqual takes two arguments of any type.

The result will be an object of the following shape. (Using TypeScript interface notation)

interface Comparison {
    matching_types: boolean,
    similarity: number,      //percentage of matching properties
    deep_equal: boolean,     //quick summary of equality
    property_count?: number, //total number of keys in an object, or length for an array
    matching?: number,       //number of deep equal properties between the two values
    differing_properties?: string[], //list of keys of properties that differed 
    common_properties?: {[index: string]: boolean},   //object containing keys of shared properties
    deep_differences?: {[index: string]: Comparison}, //the comparison object generated for each differing property
    left_only?: string[],    //keys which only appear in the left object
    right_only?: string[],    //keys which only appear in the right object
}