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Nest

Typed nested-object helpers for reading, writing, parsing, and traversing object-shaped data.

Import

import {
  Nest,
  ReadonlyNest,
  ReadonlyPath,
  nest,
  formDataToObject,
  isObject,
  makeArray,
  makeObject,
  objectFromArgs,
  objectFromFormData,
  objectFromJson,
  objectFromQuery,
  shouldBeAnArray
} from '@stackpress/lib';

When To Use It

Use Nest when your data is object-shaped, path-driven, or assembled from query strings, CLI args, or form payloads. Use ReadonlyNest when callers should only read. Use ReadonlyPath or withPath when dot notation is more convenient than variadic keys.

API

Constructor

const config = new Nest({
  database: {
    host: 'localhost',
    port: 5432
  }
});

Nest.load(data?) starts a typed builder chain and narrows the stored type as .set() calls are added.

Properties

Name Type Notes
data M Raw nested object. Nest enforces plain-object assignment.
size number Top-level key count.
withArgs ArgString Parses CLI-style arguments into the same store.
withFormData FormData Parses multipart payloads into the same store.
withPath PathString on Nest, ReadonlyPath on ReadonlyNest Dot-path access helpers.
withQuery QueryString Parses query strings into the same store.

ReadonlyNest Methods

Method Returns Notes
entries() [string, unknown][] Top-level entries.
forEach(...path, callback) Promise<boolean> Iterates arrays, objects, or strings at a path. Stops early when the callback returns false.
get(...path) typed value Returns undefined when the path is missing.
has(...path) boolean Tests whether a path is set.
keys() string[] Top-level keys.
path(notation, defaults?) typed value Dot-path read helper.
toString(expand = true, ...path) string JSON output for the whole store or a subpath.
values() unknown[] Top-level values.

Nest Methods

Method Returns Notes
clear() Nest<{}> Resets the store to an empty object.
delete(...path) this Removes one path if it exists.
set(object) narrowed Nest Merges top-level keys from a plain object.
set(...path, value) narrowed Nest Writes a nested value. Empty-string or null path segments append array items.

Path Helpers

ReadonlyPath provides:

  • get(notation, separator = '.')
  • has(notation, separator = '.')
  • forEach(notation, callback, separator = '.')

PathString adds:

  • set(notation, value, separator = '.')
  • delete(notation, separator = '.')

Callable Helper

nest(data?) returns a callable store:

const store = nest({ user: { name: 'Ada' } });

store('user', 'name');
store.get('user', 'name');
store.set('user', 'active', true);

The callable form keeps the Nest methods and reads through function invocation.

Exported Utilities

Export Purpose
formDataToObject(type, body) Converts JSON, urlencoded, or multipart bodies into a plain object.
isObject(value) Tests for plain JavaScript objects.
makeArray(object) Converts object-like numeric keys to an array.
makeObject(array) Converts an array to an object with numeric keys.
objectFromArgs(args) Parses CLI args to a plain object.
objectFromJson(json) Parses JSON safely.
objectFromQuery(query) Parses query strings to nested objects.
objectFromFormData(data) Parses multipart form data to nested objects.
shouldBeAnArray(object) Detects when a nested object should be normalized to an array.

Example

import { Nest } from '@stackpress/lib';

const request = new Nest();

request.withQuery.set('filter[type]=user&tags[]=one&tags[]=two');
request.set('meta', 'loaded', true);
request.withPath.set('profile.name', 'Ada');

const type = request.get('filter', 'type');
const firstTag = request.path<string>('tags.0');
const profile = request.get('profile');

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