https://github.com/maximilianmairinger/keyindex

Memoize on demand map
https://github.com/maximilianmairinger/keyindex

index key map memoize

Last synced: about 1 month ago
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Memoize on demand map

• Host: GitHub
• URL: https://github.com/maximilianmairinger/keyindex
• Owner: maximilianMairinger
• Created: 2020-06-30T13:54:43.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2024-03-06T14:10:27.000Z (10 months ago)
• Last Synced: 2024-11-06T18:55:45.212Z (about 2 months ago)
• Topics: index, key, map, memoize
• Language: JavaScript
• Homepage: https://www.npmjs.com/package/key-index
• Size: 40 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# Key Index

Key based index store.

## Installation

```shell

 $ npm i key-index

```

## Usage

### Create an index

Import

```ts

import keyIndex from "key-index"

```

Create an instance

```ts

let initer = (pointer: string) => {

  return {name: pointer}

}

let index = keyIndex(initer)

```

### Query

When querying a key that is not assigned to a value yet, one is automatically created via the given `initer` function.

```ts

let a = index("keyA")     // {name: "keyA"}

a.prop = "val"

index("keyA")             // {name: "keyA", prop: "val"}

```

(Mostly for debugging purposes) you can also query the whole document

```ts

let a = index()    // Map: {

                   //   "keyA": {

                   //     "name": "keyA"

                   //     "prop": "val"

                   //   }

                   // }

```

The index is stored in a Map by default. If youd like to use a regular object as index instead use

```ts

import { constructObjectIndex as keyIndex } from "key-index"

```

All functionality is the same here. The only difference is the underlying technology used. 

> Note: that native objects do only support strings | number | symbol as indices!

### Using other initers

This is the default initer

```ts

keyIndex(/* () => {return {}} */)

```

#### Using values directly

You can use values directly. If your use case does only need one value.

```ts

let valueIndex = keyIndex((key) => key)

valueIndex("keyA")                 // "keyA"

```

In that (and every other) case you can change the value like so: 

```ts

valueIndex("keyA", "keyAValue")    // "keyAValue"

valueIndex("keyA")                 // "keyAValue"

```

#### Nested indices

If using your use case requires nested indices consider this

```ts

let nestedIndex = keyIndex(() => keyIndex(/* () => {return {}} */))

nestedIndex("keyA")("keyB")         // {}

```

Querying the whole document does also work here

```ts

nestedIndex("keyA")("keyB").key = "val"

nestedIndex("keyA")("keyC").key = "val"

nestedIndex("keyD")("keyE").key1 = "val1"

nestedIndex("keyD")("keyE").key2 = "val2"

nestedIndex()                      // Map {

                                   //   "keyA": Map {

                                   //     "keyB": { key: "val" }

                                   //     "keyC": { key: "val" }

                                   //   }

                                   //   "keyD": Map {

                                   //     "keyE": { key1: "val1", key2: "val2" }

                                   //   }

                                   // }

```

> Note: Depending on the underlying technology (maps / objects) this may yield slightly different results (all maps would be regular objects).

## Contribute

All feedback is appreciated. Create a pull request or write an issue.