obstruction

Declarative parser for remapping object schemas and data

Install

$ npm install --save obstruction

Usage

var Obstruct = require('obstruction')
var parse = Obstruct({
  title: 'name',
  description: true,
  author: 'author.login'
})
parse({
  name: 'obstruction',
  description: 'Object restructuring and parsing',
  author: {
    login: 'bendrucker'
  }
})

Returns:

{
  title: 'obstruction',
  description: 'Object restructuring and parsing',
  author: 'bendrucker'
}

API

Obstruct(schema, [object]) -> function / object

If only a schema is passed, a function with the schema partially applied will be returned. You can call that function with your object.

schema

Required
Type: object

A schema object. See the schema definition options for more details.

object

Type: object

The object to parse. If omitted, a partially applied function will be returned instead.

Obstruct.array(schema) -> function

A convenience function for easily mapping arrays over a schema.

schema

Required
Type: object / function

The schema used to map array items. This can be a plain object (which will be passed to Obstruct) or the result of calling Obstruct(schema) earlier. It can also any generic function for mapping values. The following are equivalent:

Without Obstruct.array:

var parseState = Obstruct({
  abbrevation: 'abbrev'
})
Obstruct({
  states: function (states) {
    return states.map(function (state) {
      return parseState(state)
    })
  }
})

With Obstruct.array:

Obstruct({
  states: Obstruct.array({
    abbreviation: 'abbrev'
  })
})

Obstruct.optional(schema) -> function

A convenience function for easily mapping arrays over a schema.

schema

Required
Type: object / function

The schema used to parse the value, if defined (not undefined or null). This can be a plain object (which will be passed to Obstruct) or the result of calling Obstruct(schema) earlier. It can also any generic function for transforming values.

If the source value is undefined, Obstruct will immediately return undefined without calling your schema. This allows you to cleanly handle cases where a missing value might throw.

Obstruct.parent(schema) -> function

A convenience function for nested parent data within your output object.

schema

Required
Type: object / function

The schema used to parse the parent object rather than the value at the specified key.

Schema Definitions

A schema object represents the target object structure after parsing. You can nest schema objects to re-map nested objects. Schema nodes (the values in the schema object) control what value ultimately appears at a particular keypath in the final object.

Schema nodes can be:

true

The value will be copied directly from the source object:

Obstruct({foo: true})({foo: 'bar'})
// => {foo: 'bar'}

a string

The value will be copied from the source object using the supplied string as the source key:

Obstruct({foo: 'bar'})({foo: 'bar', bar: 'baz'})
// => {foo: 'baz'}

Strings can also use dot syntax to access deep properties:

Obstruct({foo: 'a.bar'})({a: {bar: 'baz'}})
// => {foo: 'baz'}

a function

The value from the source object will be passed through the supplied function:

function uppercase (string) {
  return string.toUpperCase()
}
Obstruct({foo: uppercase})({foo: 'bar'})
// => {foo: 'BAR'}

The function also receives the original object and the source key as additional arguments.

an object

Obstruct is called with the object and the source value at that keypath.

Obstruct({foo: {bar: uppercase}})({foo: {bar: 'baz'}})
// => {foo: {bar: 'BAZ'}}

an array

Schema nodes can be an array where:

• the first value is the source key to use (dot syntax is supported)
• the second value is any other valid schema node value (true, string, function, object)

Obstruct({a: ['foo', uppercase]})({foo: 'bar'})
// => {a: 'BAR'}
Obstruct({b: ['foo.bar', uppercase]})({foo: {bar: 'baz'}})
// => {b: 'BAZ'}
Obstruct({c: ['foo', {bar: uppercase}]})({foo: {bar: 'baz'}})
// => {c: {bar: 'BAZ'}}

License

MIT © Ben Drucker