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createStrategies()

createStrategies<K, In, Out>(strategies): object

Creates a strategy resolver from a record of named strategies. Replaces the GoF Context class - instead of setStrategy() + execute(), you simply pick a function by key and call it.

Type Parameters​

K: K extends string​

Union of strategy keys

In: In​

The input type

Out: Out​

The output type

Parameters​

strategies: Record<K, Strategy<In, Out>>​

Record mapping keys to strategy functions

Returns​

Resolver with use (get fn) and execute (run by key)

use(): (key) => Strategy<In, Out>​

Get a strategy by key. Typed keys only.

key: K
Returns: Strategy<In, Out>

execute(): (key, input) => Out​

Execute a strategy by key with the given input.

key: K
input: In
Returns: Out

get(): (key) => Option<Strategy<In, Out>>​

Safe lookup for dynamic/runtime keys. Returns Option<Strategy>.

key: string
Returns: Option<Strategy<In, Out>>

Since​

2.4.0

Example​

const pricing = createStrategies({
  regular: (price: number) => price,
  vip: (price: number) => price * 0.8,
  premium: (price: number) => price * 0.7,
});

const applyVip = pricing.use("vip");
applyVip(100); // 80

pricing.execute("premium", 100); // 70

// Safe lookup for dynamic keys (e.g. from config)
const key: string = getFromConfig();
pricing.get(key); // `Option<Strategy<number, number>>`

Strategy()<In, Out>​

Type

Strategy<In, Out> = (input) => Out

A Strategy is a function that transforms an input into an output. This replaces the GoF Strategy interface + concrete classes.

Type Parameters​

In: In​

The input type

Out: Out​

The output type

Parameters​

input: In​

Returns: Out​

Since​

2.4.0