node/test/module-hooks/test-module-hooks-custom-conditions-cjs.js

// Similar to test-module-hooks-custom-conditions.mjs, but checking the
// real require() instead of the re-invented one for imported CJS.
'use strict';
const common = require('../common');
const { registerHooks } = require('node:module');
const assert = require('node:assert');
const { cjs, esm } = require('../fixtures/es-modules/custom-condition/load.cjs');

(async () => {
  // Without hooks, the default condition is used.
  assert.strictEqual(cjs('foo').result, 'default');
  assert.strictEqual((await esm('foo')).result, 'default');

  // Prepending 'foo' to the conditions array in the resolve hook should
  // allow a CJS to be resolved with that condition.
  {
    const hooks = registerHooks({
      resolve(specifier, context, nextResolve) {
        assert(Array.isArray(context.conditions));
        context.conditions = ['foo', ...context.conditions];
        return nextResolve(specifier, context);
      },
    });
    assert.strictEqual(cjs('foo/second').result, 'foo');
    assert.strictEqual((await esm('foo/second')).result, 'foo');
    hooks.deregister();
  }

  // Prepending 'foo-esm' to the conditions array in the resolve hook should
  // allow a ESM to be resolved with that condition.
  {
    const hooks = registerHooks({
      resolve(specifier, context, nextResolve) {
        assert(Array.isArray(context.conditions));
        context.conditions = ['foo-esm', ...context.conditions];
        return nextResolve(specifier, context);
      },
    });
    assert.strictEqual(cjs('foo/third').result, 'foo-esm');
    assert.strictEqual((await esm('foo/third')).result, 'foo-esm');
    hooks.deregister();
  }

  // Duplicating the 'foo' condition in the resolve hook should not change the result.
  {
    const hooks = registerHooks({
      resolve(specifier, context, nextResolve) {
        assert(Array.isArray(context.conditions));
        context.conditions = ['foo', ...context.conditions, 'foo'];
        return nextResolve(specifier, context);
      },
    });
    assert.strictEqual(cjs('foo/fourth').result, 'foo');
    assert.strictEqual((await esm('foo/fourth')).result, 'foo');
    hooks.deregister();
  }
})().then(common.mustCall());