JavaScript Modules 3

Question 1

Which Node.js file extension signals that a file should be treated as an ES module?

Accepted Answer

.mjs

Answer

Node.js recognizes `.mjs` files as ES modules regardless of the `type` field in package.json.

Question 2

What is a key behavioral difference between `require()` and `import`?

Accepted Answer

`import` is statically analyzed and hoisted; `require()` is evaluated at runtime

Answer

Static `import` declarations are analyzed at parse time and hoisted, whereas `require()` executes at the point it appears in the code.

Question 3

What does `import()` (dynamic import) return?

Accepted Answer

A Promise that resolves to the module namespace object

Answer

Dynamic `import()` is an asynchronous operation that returns a Promise resolving to the module namespace object.

Question 4

In a browser ES module, how is the `defer` attribute behavior affected?

Accepted Answer

Module scripts are always deferred by default

Answer

Script tags with `type="module"` are deferred by default, executing after the document is parsed.

Question 5

What is a 'bare specifier' in ES module imports?

Accepted Answer

An import path like `'lodash'` that doesn't start with `.`, `..`, or `/`

Answer

A bare specifier is a module name like `'lodash'` with no path prefix; browsers require an import map to resolve them.

JavaScript Practice Test