esmock

esmock

(c)Bumblehead

This package must be used with node's experimental --loader,

ava --node-arguments="--loader=esmock"
mocha --loader=esmock

This package must be used with "module" type packages. Add the type to your package.json,

{
  "name": "my-module",
  "type": "module",
  "scripts" : {
    "unit-test": "ava --node-arguments=\"--loader=esmock\""
  }
}

And use it

import test from 'ava';
import esmock from 'esmock';

test('should mock module and local file at the same time', async t => {
  const main = await esmock('./local/main.js', {
    'astringifierpackage' : o => JSON.stringify(o),
    './local/util.js' : {
      exportedFunction : () => 'foobar'
    }
  });

  t.is(main(), 'foobar, ' + JSON.stringify({ test: 'object' }));
});

test('should apply third parameter "global" definitions', async t => {
  const main = await esmock('./local/main.js', {
    './local/mainUtil.js' : {
      exportedFunction : () => 'foobar'
    }
  }, {
    fs : {
      readFileSync : () => {
        return 'this value anywhere the instance imports fs, global';
      }
    }
  });

  const tplStr = main.readTemplateFile();
  t.is(tplStr, 'this value anywhere the instance imports fs, global');
});

changelog

• 0.1.0 Apr.10.2021
  • adds support for native esm modules
• 0.2.0 Apr.10.2021
  • adds support for mocking core modules such as fs and path
• 0.3.0 Apr.10.2021
  • adds support for mocking modules 'globally' for the instance