comparejs

comparejs implements JavaScript's comparison operators the way you would expect them to be.

Status

$ npm install comparejs

To use comparejs you need to reference it from your application by adding the following line:

const { compare } = require('comparejs');

If you use TypeScript, use the following code instead:

import { compare } from 'comparejs';

Supports comparison of array, boolean, function, null, number, object, string and undefined.
Supports comparison of native data types and constructor-created data types, such as number and new Number().
Supports comparison of objects and arrays using deep-equal.
Supports comparison of objects and arrays with <, <=, > and >= by handling them as subsets.
Supports comparison of objects by structure.
Supports comparison with undefined correctly, as <= and >= are problematic in plain JavaScript.
Supports comparison in a perfectly type-safe way out-of-the-box.
Supports comparison by equality and identity, depending on what makes sense.

Now you are able to use the various comparison operators. All you need to do is access the compare object and use its functions:

Operator	Alias	Description
`equal(left, right)`	`eq(left, right)`	equal
`notEqual(left, right)`	`ne(left, right)`	not equal
`lessThan(left, right)`	`lt(left, right)`	less than
`lessThanOrEqual(left, right)`	`lte(left, right)`	less than or equal
`greaterThan(left, right)`	`gt(left, right)`	greater than
`greaterThanOrEqual(left, right)`	`gte(left, right)`	greater than or equal
`identity(left, right)`	`id(left, right)`	identity

Please note that each comparison operator works on each combination of types and does what you would expect it to do.

For objects, there are special operators that compare by structure. Among other things, they can be used to verify objects against interfaces:

Operator	Alias	Description
`equalByStructure(left, right)`	`eqs(left, right)`	equal by structure
`notEqualByStructure(left, right)`	`nes(left, right)`	not equal by structure
`lessThanByStructure(left, right)`	`lts(left, right)`	less than by structure
`lessThanOrEqualByStructure(left, right)`	`ltes(left, right)`	less than or equal by structure
`greaterThanByStructure(left, right)`	`gts(left, right)`	greater than by structure
`greaterThanOrEqualByStructure(left, right)`	`gtes(left, right)`	greater than or equal by structure

Please note that these operators only work for objects. For any other type, they return false.

To run quality assurance for this module use roboter:

$ npx roboter