fromJSON

Parses a JavaScript object previously serialised as aMaybe.toJSON() into a proper Maybe structure.

This feature is experimental!

This API is still experimental, so it may change or be removed in future versions. You should not rely on it for production applications.

Signature

fromJSON(value, parsers = { [typeName]: adt }, keysIndicateType = false)

Type(what is this?)

type JSONSerialisation = {
  "@@type":  String,
  "@@tag":   String,
  "@@value": Object Any
}
type JSONParser = {
  fromJSON: (JSONSerialisation, Array JSONParser) => Variant
}

(JSONSerialisation, Array JSONParser) => Variant

Documentation

Parses a JavaScript object previously serialised as aMaybe.toJSON() into a proper Maybe structure.

See the docs for adt/union/derivations/serialization for more details.

Example:

const Maybe = require('folktale/maybe');

Maybe.fromJSON(Maybe.Just(1).toJSON());
// ==> Maybe.Just(1)

Maybe.fromJSON(Maybe.Nothing().toJSON());
// ==> Maybe.Nothing()

Properties

Source Code

function(value, parsers = { [typeName]: adt }, keysIndicateType = false) {
    const valueTypeName = value[typeJsonKey];
    const valueTagName = value[tagJsonKey];
    const valueContents = value[valueJsonKey];
    assertType(typeName, valueTypeName);
    const parsersByType = keysIndicateType ? parsers
          : /*otherwise*/                    indexByType(values(parsers));

    const parsedValue = mapValues(valueContents, parseValue(parsersByType));
    return extend(Object.create(adt[valueTagName].prototype), parsedValue);
  }