How to import an ES module in Node.js REPL?

Question

I have an ES6 module right.mjs. Executing it as a parameter to node works well:

$ node --version v8.10.0  $ node --experimental-modules right.mjs (node:4492) ExperimentalWarning: The ESM module loader is experimental. executing right module `executing right module` is the output of the module. 

In contrast to that, the following input in the REPL waits for further input:

$ node --experimental-modules > (node:4526) ExperimentalWarning: The ESM module loader is experimental.  > import 'right.mjs'; ... 

I don't understand why.

The same with:

> import './right.mjs'; ... 

Trying to require results in:

> require('./right.mjs'); Error [ERR_REQUIRE_ESM]: Must use import to load ES Module: /home/xxx/right.mjs     at Object.Module._extensions..mjs (module.js:686:11)     at Module.load (module.js:565:32)     at tryModuleLoad (module.js:505:12)     at Function.Module._load (module.js:497:3)     at Module.require (module.js:596:17)     at require (internal/module.js:11:18) 

So, how can I import an ES module in the Node.js REPL?

Answer 1

It is possible in Node.js v14, but you need to use the import function, rather than the import statement.

$ node  Welcome to Node.js v14.4.0. Type ".help" for more information. > let myModule; undefined > import("./my-module.js").then(module => { myModule = module }); Promise { <pending> } > myModule.foo(); "bar"