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js-testDiff

About

Deep object diffing function for JavaScript; returns true if input 1 differs in any way from input 2. Original code was taken from Differentia.js and ported to TypeScript.

The testDiff function was originally created as a unit testing utility and it was primarily designed/used to test Differentia's search algorithm strategy system, setting a "gold standard" for that library's quality and algorithmic correctness.

The key difference with this version of testDiff is that I removed its "search index" functionality, as it introduced more complexity than it was worth.

Feel free to scavenge the original code as I have: https://github.com/Floofies/Differentia.js/blob/master/spec/testUtils.js

Building

Run npm run build to compile and test module dist/index.js.

I have pre-compiled the most up-to-date files in dist. Enjoy.

unitTest.js can be safely ignored, as it's a development-only dependency for test.mjs.

Syntax

import { testDiff } from "testDiff";

testDiff( input1:any, input2:any, [ deep:boolean = false ] );

Parameters:

`input1`, `input2`

Two values/objects to compare against each other.

`deep` (Optional) (Default = `true`)

TestDiff performs "deep" object/array traversal by default, comparing all reachable values; set this operand to false to disable traversal and nested comparisons.

Return Value:

Returns true if input1's structure, properties, or values differ in any way from input2, or false if otherwsie.

Usage Examples

Example 1: Arbitrary values.

Can handle any arbitrary values, as well as objects/arrays.

const myArray1 = "Hello World!";
const myArray2 = "This is a test";
const result = testDiff(myArray1, myArray2);
// result = true

Example 2: Flat arrays/objects.

const myArray1 = [1,2,3];
const myArray2 = [4,5,6];
const result = testDiff(myArray1, myArray2);
// result = true

Example 3: Nested arrays/objects.

const myArray1 = ["Hello",["World!"]];
const myArray2 = ["Hello",["Developer!"]];
const result = testDiff(myArray1, myArray2);
// result = true

Example 4: Nested arrays. Traversal disabled.

In this example, the function returns false even though the arrays' contents differ; they are regarded as the same because there are no differences at the top, and disabling traversal prevents the algorithm from seeing deeper differences.

const myArray1 = ["Hello",["World!"]];
const myArray2 = ["Hello",["Developer!"]];
const result = testDiff(myArray1, myArray2, false);
// result = false