visotype/node-elm-eval

A promise API for executing Elm function calls in JavaScript (experimental)

This package includes an Elm port module that wraps visotype/elm-eval and a Node module that provides a JavaScript interface to the compiled Elm program. It is designed for use with the ES2017 async/await syntax.

Usage

const { expr } = require('node-elm-eval');

(async () => {
  try {
    const result = await expr('(+)', 1, 2);
    console.log(result);
  } catch (error) {
    console.log(error.message);
  }
})();

API

expr(f, ...args)

Returns a promise for the JavaScript value type corresponding to the Elm function's return value.

f

Type: string

The name of an Elm function. The module name should be included, as in 'String.length' or 'List.append', but may be omitted for functions in the Basics module like 'always' or 'round'. Operators should be enclosed in parentheses like '(+)' or '(::)'.

args

Arguments to f. Types must correspond to the Elm function's type signature. Will return a rejected promise if there are too many or too few arguments or type decoding fails.

call({ f, args })

Same as expr, but takes a call object as its argument.

f

Type: string

Same as above.

args

Type: array

Same as with expr, but given as an array.

partialExpr(f, args)

Returns a function that will evaluate to a promise when the missing argument is supplied.

f

Type: string

Same as above.

args

Same as with expr, but missing the last (rightmost) argument

partialCall({ f, args })

Same as partialExpr, but takes a call object as its argument.

f

Type: string

Same as above.

args

Same as with partialExpr, but given as an array.