Introduction

The Smart Matcher overrides Jasmine's toEqual() matcher and gives you phenomenal granularity in complex object or string comparisons. If you are heavy on Test-Driven Development, this is a matcher you can't live without.

Here's an example:

var string1 = "Yankee Doodle went to town, riding on a pony."
var string2 = "Yankee Doodle went to twon, riding on a pony."
expect(string1).toEqual(string2);

This produces the following failure message:

Mismatch in character 23 when Comparing
kee Doodle went to twon, riding on a pon
                    ^
with
kee Doodle went to town, riding on a pon
                    ^
<===EXPECTED Yankee Doodle went to twon, riding on a pony. ==> with <===ACTUAL Yankee Doodle went to town, riding on a pony. ==>

This pinpoints the precise location of the mismatch, and gives you enough of a preview snippet to get context.

Advanced objects and arrays are also handled to show clear points of mismatch.

For example, here is an object of arrays:

describe("Object of arrays", function () {
    let sprintRecords = {
        UsainBolt: [10,11,1.5],
        CarlLewis: [12,13,2]
    };
    it("mismatch", function() {
        let otherSprintRecords = {
            UsainBolt: [12,11,1.5],
            CarlLewis: [12,15,2]
        };
        expect(otherSprintRecords).toEqual(sprintRecords);
    });

});

The above test produces the following failure:

Mismatch in key 'UsainBolt':
    Item 0 had a mismatch.
	    Expected 12 to be 10

Mismatch in key 'CarlLewis':
    Item 1 had a mismatch.
	    Expected 15 to be 13

Let's now look at an array of objects:

describe("Array of objects", function () {
    let citiesInBayArea = [
        { "name": "Menlo Park", population: 10000},
        { "name": "Mountain View", population: 20000}
    ];
    it("mismatch", function() {
        let anotherListOfCitiesInBayArea = [
            { "name": "Menla Park", population: 15000},
            { "name": "Moontain View", population: 21000}
        ];
        expect(anotherListOfCitiesInBayArea).toEqual(citiesInBayArea);
    });

});

This produces the following failure:

    Item 0 had a mismatch.
        Mismatch in key 'name':
            Mismatch in character 4 when Comparing
            Menlo Park
                ^
            with
            Menla Park
                ^
            <===EXPECTED Menlo Park ==> with <===ACTUAL Menla Park ==>
        
        Mismatch in key 'population':
            Expected 15000 to be 10000

    Item 1 had a mismatch.
        Mismatch in key 'name':
            Mismatch in character 2 when Comparing
            Mountain View
              ^
            with
            Moontain View
              ^
            <===EXPECTED Mountain View ==> with <===ACTUAL Moontain View ==>
        
        Mismatch in key 'population':
            Expected 21000 to be 20000

Installation

Run:

bower install smart-jasmine-matcher --save-dev

Include bower_components/smart-jasmine-matcher/src/smartJasmineMatcher.js in your src imports.

Then, before all your jasmine tests, add this code:

beforeEach(function () {
    jasmine.addMatchers(smartorg.test.matchers.smartMatcher);
});

That's it! Continue using toEqual as you may already have. Note that you must be on Jasmine 2 or higher.