schema

• schema<T>(store: T | Readable<T> | Writable<T>, json_schema: JsonSchema, start?: IStoreStartStopNotifier<T>): Readable<T> | Writable<T>

• Returns a Readable / Writable Svelte Store, that validates values set to the Store, and retrieved via subscriptions, against a JSON Schema

  NOTE: If a non-Store value is passed as store, then it will be wrapped in a Writable Store

  import {schema} from "svelte-commons/lib/stores/shared";
  
  // Here, we're defining our JSONSchema that will validate our I/O
  //
  // Check out for more information: https://json-schema.org/
  const person_schema = {
      $id: "https://example.com/person.schema.json",
      $schema: "http://json-schema.org/draft-07/schema#",
      title: "Person",
      type: "object",
      properties: {
          firstName: {
              type: "string",
              description: "The person's first name."
          },
  
          lastName: {
              type: "string",
              description: "The person's last name."
          },
  
          age: {
              description: "Age in years which must be equal to or greater than zero.",
              type: "integer",
              minimum: 0
          }
      }
  };
  
  // We need to seed our with an initial value, so here's a sample person
  const initial_person = {
      firstName: "John",
      lastName: "Smith",
      age: 32
  };
  
  // Now we just pass our initial data and our JSON Schema in
  const store = schema(initial_person, person_schema);
  
  // To demonstrate changes, we need to log each change
  store.subscribe(console.log); // logs: `{firstName: "John", lastName: "Smith", age: 32}`
  
  // Here, we're copying our initial "Person", then updating its age to `21`
  store.set({...initial_person, age: 21}); // logs: `{firstName: "John", lastName: "Smith", age: 21}`
  
  // Same as above, but using a negative `.age` to have an exception thrown
  store.set({...initial_person, age: -60}); // throws exception: `Uncaught TypeError: bad change 'Person/age' to Schema Store (Value -60 is less than minimum 0)`

  Type parameters

  • T: IJSONType

  Parameters

  • store: T | Readable<T> | Writable<T>

  • json_schema: JsonSchema

  • Optional start: IStoreStartStopNotifier<T>

  Returns Readable<T> | Writable<T>