Tailspin

Object path accessor. Tests, provides and sets values within objects and arrays.

Installation

$ npm install --save @konfirm/tailspin

Usage

Provide an object and a path (as string) to the tailspin module and a new Tail object is returned.

const tailspin = require('@konfirm/tailspin');
const subject = { foo: { bar: { baz: 1 } } };
const tail = tailspin(subject, 'foo.bar.baz');

console.log(tail.value);  //  1

tailspin(scope, path)

Create a Tail-instance to interact with the provided path within the scope.

Tail-API

A Tail object is what is returned by the tailspin-function, it provides several members to interact with the provided target/path. All of the examples in the API outline below use the tail created in the example in usage.

value

Obtain the value of the Tail-object.

console.log(tail.value);  //  1

(bool) modify(value [, force=false])

Modify the value of the Tail-object, can be forced in case the path in itself is not reachable.

tail.modify(2);  //  returns true, success
console.log(tail.value);  //  2

type

Obtain the type of the Tail-object. Returns one of the regular javascript typeof types ('boolean', 'number', 'string', 'object', 'null' or 'undefined'), or 'array' in case the value is an array.

console.log(tail.type);  //  number

types

Obtain all types encountered during traversal of the path leading up to the Tail-object. Uses the same values for types as provided by type.

console.log(tail.types);  //  [ 'object', 'object', 'number' ]
                          //     ^ foo     ^ bar     ^ baz

reachable

Determine whetehr the path of the Tail-object is actually reachable. Reachable in this context means whether of not the path exists or can be created without changing any type other than array, object or undefined.

console.log(tail.reachable);  //  true

If any value of the path is not capable (or desirable) to have a property, it is considered to be unreachable. For example, one cannot set a property to a number value.

const subject = { num: 1 };
const tail = tailspin(subject, 'num.property');

console.log(tail.reachable);  //  false

scope

Obtain the scope of the Tail-object. This will be the "parent" Tail-object, if any.

console.log(tail.scope);

License

MIT License Copyright (c) 2017 Rogier Spieker (Konfirm)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.