PureParse

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JSON ​

PureParse provides some functionality for parsing JSON strings.

Parsing JSON strings (parseJson) ​

parseJson is a wrapper around JSON.parse which catches any errors and turns them into failures. The Result type is JsonValue (unlike JSON.parse, which returns any):

ts
parseJson('{"key": "value"}') // -> ParseSuccess<JsonValue>
parseJson('123') // -> ParseSuccess<JsonValue>

The value must be a JSON-string:

ts
parseJson('not a json string') // -> ParseFailure
parseJson(123) // -> ParseFailure
parseJson(null) // -> ParseFailure

Validating the Parsed Results With chain ​

To validate that the parsed JSON adhere, chain together parseJson with a custom parser:

ts
const parseUserJson = chain(parseJson, parseUser)

parseUserJson('{"name": "John", "age": 30}') // -> ParseSuccess<User>

Validating JSON values (isJsonValue) ​

To verify that a value can be encoded as JSON—without any custom encoding—use isJsonValue:

ts
isJsonValue('abc') // -> true
isJsonValue({ key: 'value' }) // -> true
isJsonValue([1, 2, 3]) // -> true

isJsonValue(new Date()) // -> false
isJsonValue(() => {}) // -> false
isJsonValue(Symbol('foo')) // -> false