walt-compiler/src/__tests__/type-imports-spec.js

Alternative syntax for WebAssembly text format

import test from 'ava';
import parser from '../parser';
import generateImportFromNode from '../generator/import';
import { compileAndRun } from '../utils/test-utils';

test('function typed imports', t => {
  // What is happening here:
  // We are creating a module which takes an import of console.log
  // we provide this import to the module in the second param. We
  // then invoke the test() function exported from the module and
  // test that the correct value was echo-ed back to us!
  return new Promise(resolve => {
    compileAndRun(
      `
      import { log: Log } from 'env';
      type Log = (i32) => void;
      export function test(x: i32): void {
        log(42);
      }
    `,
      {
        env: {
          log: function(value) {
            t.is(value, 42);
            resolve();
          },
        },
      }
    ).then(result => result.instance.exports.test(4434));
  });
});

test('function pointers', t =>
  new Promise(resolve => {
    const table = new WebAssembly.Table({ element: 'anyfunc', initial: 10 });
    compileAndRun(
      `
      import { table: Table<{ initial: 20 }> } from 'env';
      import { setTimeout: Later } from 'env';
      import { log: Log } from 'env';

      type Log = (i32) => void;
      type Later = (Function, i32) => void;

      function echo(): void {
        log(42);
      }

      export function test(): void {
        setTimeout(echo, 5);
      }
    `,
      {
        env: {
          table,
          log: function(value) {
            t.is(value, 42);
            resolve();
          },
          setTimeout: (functionPointer, timeout) => {
            const func = table.get(functionPointer);
            setTimeout(func, timeout);
          },
        },
      }
    ).then(result => result.instance.exports.test());
  }));

test('import expression generator', t => {
  const node = parser(
    [],
    "import { field: i32, foo: CustomType, bar: SomeOtherType } from 'env';"
  );
  t.snapshot(generateImportFromNode(node.params[0]));
});