json.mdx

title	description	canonical
JSON	Interacting with JSON in ReScript	/docs/manual/latest/json

JSON

Parse

Bind to JavaScript's JSON.parse and type the return value as the type you're expecting:

<CodeTab labels={["ReScript", "JS Output"]}>

// declare the shape of the json you're binding totypedata= {names: array<string>} // bind to JS' JSON.parse @scope("JSON") @valexternalparseIntoMyData: string=>data="parse"letresult=parseIntoMyData(`{"names": ["Luke", "Christine"]}`) letname1=result.names[0]

varresult=JSON.parse("{\"names\": [\"Luke\", \"Christine\"]}");varname1=result.names[0];

Where data can be any type you assume the JSON is. As you can see, this compiles to a straightforward JSON.parse call. As with regular JS, this is convenient, but has no guarantee that e.g. the data is correctly shaped, or even syntactically valid. Slightly dangerous.

Stringify

Use Js.Json.stringify:

<CodeTab labels={["ReScript", "JS Output"]}>

Js.log(Js.Json.stringifyAny(["Amy", "Joe"]))

console.log(JSON.stringify(["Amy","Joe"]));

Advanced

The Js.Json module provides slightly safer, low-level building blocks for power users who want to parse JSON on a per-field basis. See the examples in the API docs.