sorting-lib

Sorting Lib

Javascript has no built-in ways to easily handle the comparison between objects. This is why this library exists, it provides an intuitive API to create comparators.

Install by running:

npm i sorting-lib

The project is maintained on Gitlab

Comparing

With you comparing function you can select a key to compare by. Selecting a key happens by either a dot-seperated string or a lambda function.

const array = [
	{ value: 1, object: { subValue: 1 } },
	{ value: 2, object: { subValue: 2 } },
];

array.sort(comparing(item => item.value));
array.sort(comparing(item => item.object.subValue));
array.sort(comparing('value'));
array.sort(comparing('object.subValue'));

Handling Nil

You can choose Nil (null | undefined) values to be either a maximum or a minimum:

const array = [
	{ value: 1 },
	{},
];

array.sort(comparing(item => item.value), NilAs.Max);

Comparator builder

For more complex sorting needs you can combine multiple "simple" comparators into one. An example where this might be useful is sorting names.

type Person = { firstName: string, lastName: string }

const fullNames = [
	{ firstName: 'a', lastName: 'b' },
	{ firstName: 'a', lastName: 'c' },
];

fullNames.sort(
	// Compares `firstName` first, then falls back to `lastName`
	comparatorBuilder<Person>()
		.add(comparing('firstName'))
		.add(comparing('lastName'))
		.build(),
);

Note: as of now typescript's type inference is not strong enough to infer the Person type

Invert

Inverting a comparison:

// Inverts the comparison
comparatorBuilder<SomeType>()
	.add(someComparator)
	.invert()
	.build()

Combining a dynamic array of comparators

declare const arrayOfComparators: Comparator<SomeType>[];

const combinedComparator: Comparator<SomeType> =
	chainComparators(arrayOfComparators);