js.bend source

js.bend on the hub · documented module

import Baseimport bend-kit-json@0.3.0.0/json.bend as Json# Host boundary: JavaScript source in, JSON text or an error out.# A future C/JavaScriptCore effect can implement this same signature.def eval_json(source: String) -> IO(Result<&2, &2, String, String>):  import "./eval.js"def decoded(value: Maybe<&2, Json.Val>) -> Result<&2, &2, String, Json.Val>:  match value:    case Some{json}:      Done{json}    case None{}:      Fail{"decode: the JavaScript effect returned invalid JSON."}def decode(result: Result<&2, &2, String, String>) -> Result<&2, &2, String, Json.Val>:  match result:    case Done{text}:      decoded(Json.parse(text))    case Fail{message}:      Fail{message}# Evaluate synchronously, then turn the JSON snapshot into a Bend value.def eval(source: String) -> IO(Result<&2, &2, String, Json.Val>):  do IO<Result<&2, &2, String, Json.Val>>:    result : Result<&2, &2, String, String> <- eval_json(source)    return decode(result)