array-deduper
v1.0.0
Published
Deduplicates items in an array
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Array Deduper
A method for deduplicating items in an array, returning a new Array.
Items are deduplicated in order, with the first occurrence of an item being the item returned in the results.
An optional key mapper can be provided to specify how to deduplicate the items.
The dedupe()
method can be added as an extension of the native JS Array
interface.
const result1 = dedupe(
["1", "2", "1"]
) // returns ["1", "2"]
const result2 = ["1", "2", "1"].dedupe() // returns ["1", "2"]
Installation
npm install --save array-deduper
Documentation
Extending Array
with dedupe()
To add the dedupe()
method to JS's base Array
interface, you can import the extension by including:
import "array-deduper/extend-array-with-dedupe"
into your codebase at some point before attempting to call [].dedupe()
// somewhere in your initialization logic
import "array-deduper/extend-array-with-dedupe"
// ...
// Array now has a dedupe() method
const result = ["1", "2", "1"].dedupe() // returns ["1", "2"]
Deduping Objects
The Array Deduper will deduplicate objects in an Array.
By default, it converts the objects to strings using JSON.stringify()
and then deduplicates those strings.
const result = dedupe(
[
{id: "1", a: "1"},
{id: "2", a: "1"},
{id: "1", a: "2"},
{id: "1", a: "1"}
]
)
// returns [
// {id: "1", a: "1"},
// {id: "2", a: "1"},
// {id: "1", a: "2"}
// ]
Deduplicating objects based on an attribute
If the objects needed to be deduplicated based on some custom property, a keyMapper
function can be passed to the function.
The keyMapper
takes the input object and maps it to a string, that string is then used to deduplicate the objects.
A standard usecase for this is if the objects all have some kind of id
property which is used to determine uniqueness amongst them.
const result = dedupe(
[
{id: "1", a: "1"},
{id: "2", a: "1"},
{id: "1", a: "2"},
{id: "1", a: "1"}
],
item => item.id
)
// returns [
// {id: "1", a: "1"},
// {id: "2", a: "1"}
// ]