@punchcard/shape-jsonpath

This library extends the Punchcard Shape Type-System with support for a type-safe JSON path generator.

Define a Type

// a record to be used within our top-level type (i.e. a nested structure).
export class Nested extends Record({
  /**
   * This is a nested string.
   */
  a: string
}) {}

// the type we will query with JSON path
export class MyType extends Record({
  /**
   * Field documentation.
   */
  id: string,
  count: number,
  array: array(string),
  complexArray: array(Nested),
  map: map(string),
  complexMap: map(Nested)
}) {}

Derive a JSON Path DSL from the type

const _ = JsonPath.of(MyType);

Create a JSON Path

_ is a type-safe DSL with members and operators that correspond to a JSON path expressions.

Use JsonPath.compile(expr) to compile the abstract JSON path to its string representation. E.g JsonPath.compile(_.id) === "$['id']".

Access a member

_.id; // $['id']

Filter items in array

_.array.filter(_ => _.equals('value')); // $['array'][?(@=='value')]
_.complexArray.filter(_ => _.a.equals('value')); // $['complexArray'][?(@['a']=='value')]

Access a map's value

_.map.item; // $['map']['item']
_.map.get('item'); // $['map']['item']

Filter a map by value

_.map.filter(_ => _.equals('value')); // $['map'][?(@=='value')]
_.complexMap.filter(_ => _.a.equals('value'); // $['complexMap'][?(@['a']=='value')]