shackles

A minimal chaining library with tapping and logging

Install

$ npm install --save shackles

Basic Usage

Add chaining to a library:

var stringlib = {
	prepend: function(str, chr) {
		return chr + str
	},
	append: function(str, chr) {
		return str + chr
	}
}

var chain = shackles(stringlib)

var result = chain('Hello')
	.prepend('(')
	.append('!')
	.append(')')
	.value() // (Hello!)

If underscore didn't have chaining, we could easily add it:

var chain = shackles(_)

var result = chain([1,2,3])
	.map(function (x) { return x*x })
	.filter(function (x) { return x > 2 })
	.value() // [4,9]

Scalar properties become chainable methods that override the underlying value:

var chain = shackles({
	inc: function(x) { return x+1 }
	pi: 3.141592654
})

var result = chain(0)
	.inc()
	.inc()
	.num()
	.inc()
	.value() // 4.141592654

Tapping

You can transform the value at any point in the chain:

var chain = shackles(/* lib */)

var result = chain(10)
	.tap(function(value) {
		return value * 2;
	})
	.value() // 20

Logging

You can log the value at any point in the chain: The default logger method is console:

var chain = shackles({
	inc: function(x) { return x+1 }
})

var result = chain(0)
	.inc()
	.log() // 1
	.inc()
	.log() // 2
	.inc()
	.inc()
	.value() // 4

You can override the default logger:

var doubled = null

var chain = shackles({}, {
	logger: {
		log: function(value) {
			doubled = value * 2
		}
	}
})

var result = chain(10)
	.log()
	.value() // 10

console.log(doubled) // 20

You can enable/disable logging for longer sections of the chain:

var history = []

var stringlib = {
	prepend: function(str, chr) {
		return chr + str
	},
	append: function(str, chr) {
		return str + chr
	}
}

var chain = shackles(stringlib, {
	logger: {
		log: function(value) {
			history.push(value)
		}
	}
})

var result = chain('Hello')
	.log(true)
	.prepend('(')
	.append('!')
	.append(')')
	.log(false)
	.append('?')
	.append('?')
	.append('?')
	.value() // (Hello!)???

console.log(history) 
/* [
	'Hello',
	'(Hello',
	'(Hello!',
	'(Hello!)'
]) */

License

ISC © Raine Lourie