TypedRecord

A type-safe record with 0 dependencies.
Aren't you sick of creating a Record or Map without strictly knowing the type of the values?

For example:

const record: Record<string, number | string | undefined> = {
    thisIsANumber: 5
};

// Much Later in your code.....
let iWouldLikeToBeOfTypeNumber = record.thisIsANumber // The type would be "string | number | undefined" unfortunately...


//// It's even worse with Maps

const myMap = new Map();

myMap.set('thisIsANumber', 5)

iWouldLikeToBeOfTypeNumber = myMap.get('thisIsANumber') // What?? You should not get any... If there was a solution?

So you can chill out and just use TypedRecord instead.

import { TypedRecord } from 'typed-record';

const typedRecord = new TypedRecord();
const myKey = typedRecord.set('aNameForTheKey', 5);

const aNumber = typedRecord.get(myKey) // The type is "number"!!!

Simple as that.

When you should use it

I would only recommend using this pattern when you have a "pluggable" (when you compose stuff) flow where the main flow does fully aware of the type of the values. This pattern will give you the advantaged of dynamic pluggable typings and communication between the plug-ins.

• I call it plug-in but you can name it whatever you like, component, feature etc...

Installation

npm i typed-record

or

yarn add typed-record

Usage

set

Set a typed value in the record

@param key - A string that represent the symbol name or the key (Symbol) that holds the type of the value

@param value - the value to set

@returns returns the key that is used to retrieve the value

const typedRecord = new TypedRecord();
// The key is created for you automatically
const myKey = typedRecord.set('my-key', { hello: 'world' });

// Manually creating the key
const manuallyCreatedKey = TypedRecord.key<number>('a-key');
typedRecord.set(manuallyCreatedKey, 69);

get

The get method returns the value associated with the specified key

@param key - the key (Symbol) that holds the type of the value

@returns the typed value or undefined if it doesn't exist

const typedRecord = new TypedRecord();
const myKey = typedRecord.set('my-key', { hello: 'world' });

const value = typedRecord.get(myKey); // The type would be "{ hello: 'world' }"

has

The has method returns a boolean indicating whether an element with the specified key exists or not.

@param key - the key (Symbol) that holds the type of the value

@returns returns true if the record contains the specified key

const typedRecord = new TypedRecord();

const myKey = typedRecord.set('my-key', { hello: 'world' });

typedRecord.has(myKey); // true
typedRecord.has(TypedRecord.key('does-not-exist-key')); // false

delete

The delete method removes the specified element from the TypedRecord by key.

@param key - the key (Symbol) that holds the type of the value

@returns returns true if the record contained the specified element

const typedRecord = new TypedRecord();

const myKey = typedRecord.set('my-key', { hello: 'world' });

typedRecord.delete(myKey); // true
typedRecord.delete(TypedRecord.key('does-not-exist-key')); // false

clear

The clear method removes all elements from a record object.

Creating a key Manually

To get your typed value from the record you need to create a key (Symbol) that holds the type of the value.

@param name - description of the key

@returns return a typed symbol that can be used to access the value

const key = TypedRecord.key<{ hello: 'world' }>('test');

License

MIT

Contributing

Feel free to fork and create pull requests!

Important note

Special thanks to my colleagues at Stylable for the knowledge sharing.