@jrh/rely v2.0.0

@jrh/rely

Simple dependency injection for Node.js functions.

Installation

npm install @jrh/rely

Usage

const rely = require('@jrh/rely')

const reliant = rely.on(dependencies).to(original)

reliant.provide(provided).run()

Specifying Dependencies

.on(dependencies)

Arguments

.to(original)

Arguments

Example

function combine(base, { a, b, c }) {
  return base + a + b + c
}

const reliant = rely.on('a', 'b', 'c').to(combine)

Providing Dependencies

.provide(dependencies)

Arguments

Exceptions

Throws a standard Error if not all specified dependencies were provided, or any dependency is undefined.

.run(arguments)

Arguments

Example

function combine(base, { a, b, c }) {
  return base + a + b + c
}

const reliant = rely.on('a', 'b', 'c').to(combine)

reliant
  .provide({ a: 1, b: 2, c: 3 })
  .run(10)
  // => 15

Usage Example

jump.js

const rely = require('@jrh/rely')

function jump(power, { jumpStrategy }) {
  return jumpStrategy(power)
}

module.exports = rely.on('jumpStrategy').to(jump)

jump.strategies.js

function ground(power) {
  return power * 1
}

function trampoline(power) {
  return power * 10
}

module.exports = { ground, trampoline }

index.js

const jump = require('./jump')
const { ground, trampoline } = require('./jump.strategies')

jump.provide({ jumpStrategy: ground }).run(5) // => 5
jump.provide({ jumpStrategy: trampoline }).run(5) // => 50