What is the syntax to export a function from a module in Node.js?
function foo() {}
function bar() {}
export foo; // I don't think this is valid?
export default bar;
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1Possible duplicate of What is "export default" in javascript?Erazihel– Erazihel2017-07-18 16:05:57 +00:00Commented Jul 18, 2017 at 16:05
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5Absolutely not a duplicate. This is a matter of feature support in the current Node build. What's with the downvotes, people?salezica– salezica2017-07-18 16:07:47 +00:00Commented Jul 18, 2017 at 16:07
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4 Answers
In Node you export things with module.exports special object. For example:
This exports both functions:
module.exports = { foo, bar };
They can be used as:
const { foo, bar } = require('./module/path');
To export one of those functions as top-level object you can use:
module.exports = foo;
module.exports.bar = bar;
which can be used as:
const foo = require('./module/path');
and:
const { bar } = require('./module/path');
or:
const foo = require('./module/path');
const { bar } = foo;
or:
const foo = require('./module/path');
const bar = foo.bar;
etc.
This is "the syntax to export a function from a module in Node.js" as asked in the question - i.e. the syntax that is natively supported by Node. Node doesn't support import/export syntax (see this to know why). As slezica pointed put in the comments below you can use a transpiler like Babel to convert the import/export keywords to syntax understood by Node.
See those answers for more info:
2 Comments
Ben Aston
Ah, thank you. And what is the ES2015 module syntax for the same?
salezica
This is the only way until Node starts supporting
import/export ES6 syntax, which it currently does not. You can also use Babel, installing babel-cli and babel-preset-latest as dev-dependencies, then precompiling your javascript or running babel-node. I do this for all my projectsexport function foo(){...};
Or, if the function has been declared earlier:
export {foo};
Reference: MDN export
Comments
to expose both foo and bar functions:
module.exports = {
foo: function() {},
bar: function() {}
}
Comments
You can also do this in a shorter form
// people.js
function Foo() {
// ...
}
function Bar() {
// ...
}
module.exports = { Foo, Bar}
Importing:
// index.js
const { Foo, Bar } = require('./people.js');
Comments
