Node js - SyntaxError Unexpected token import

Question

I don t understand what is wrong  Node v5 6 0 NPM v3 10 6  The code    function  exports  require  module    filename    dirname        import express from  express       The error   SyntaxError  Unexpected token import     at exports runInThisContext  vm js 53 16      at Module  compile  module js 387 25      at Object Module  extensions  js  module js 422 10      at Module load  module js 357 32      at Function Module  load  module js 314 12      at Function Module runMain  module js 447 10      at startup  node js 140 18      at node js 1001 3

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I ve been trying to get this working  Here s what works   Use a recent node version  I m using v14 15 5  Verify your version by running  node --version Name the files so that they all end with  mjs rather than  js   Example  mod mjs export const STR    Hello World   test mjs import  STR  from    mod mjs  console log STR   Run  node test mjs You should see  quot Hello World quot

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I often use a github starter project  like this  it uses babel

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I m shocked esm hasn t been mentioned  This small  but mighty package allows you to use either import or require   Install esm in your project    npm install --save esm  Update your Node Start Script to use esm  node -r esm app js  esm just works  I wasted a TON of time with  mjs and --experimental-modules only to find out a  mjs file cannot import a file that uses require or module exports  This was a huge problem  whereas esm allows you to mix and match and it just figures it out    esm just works

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I m going to address another problem within the original question that no one else has   After recently converting from CommonJS to ESM in my own NodeJS project  I ve seen very little discussion about the fact that you cannot place imports wherever you want  like you could with require   My project is working great with imports now  but when I use the code in the question  I first get an error for not having a named function   After naming the function  I receive the following    import express from  express                  SyntaxError  Unexpected identifier     at Loader moduleStrategy  internal modules esm translators js 88 18   You cannot place imports inside functions like you could require   They have to be placed at the top of the file  outside code blocks   I wasted quite a bit of time on this issue myself  So while all of the above answers are great at helping you get imports to work in your project  none address the fact that the code in the original question cannot work as written

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In case that you still can t use  import  here is how I handled it  Just translate it to a node friendly require  Example   import   parse   from  node-html-parser     Is the same as   const parse   require  node-html-parser   parse

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As mentioned in other answers Node JS currently doesn t support ES6 imports    As of now  read  EDIT 2   Enable ES6 imports in node js provides a solution to this issue  I have tried this and it worked for me   Run the command       npm install babel-register babel-preset-env --save-dev   Now you need to create a new file  config js  and add the following code to it       require  babel-register             presets     env                  Import the rest of our application      module exports   require    your server file js     Now you can write import statements without getting any errors   Hope this helps   EDIT   You need to run the new file which you created with above code  In my case it was config js  So I have to run       node config js   EDIT 2   While experimenting  I found one easy solution to this issue   Create  babelrc file in the root of your project   Add following  and any other babel presets you need  can be added in this file                   presets     env           Install babel-preset-env using command npm install babel-preset-env --save  and then install babel-cli using command npm install babel-cli -g --save  Now  go to the folder where your server or index file exists and run using          babel-node fileName js  Or you can run using npm start by adding following code to your package json file        scripts              start    babel-node src index js

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Update 3  Since Node 13  you can use either the  mjs extension  or set  type    module  in your package json  You don t need to use the --experimental-modules flag   Update 2  Since Node 12  you can use either the  mjs extension  or set  type    module  in your package json  And you need to run node with the --experimental-modules flag   Update  In Node 9  it is enabled behind a flag  and uses the  mjs extension    node --experimental-modules my-app mjs     While import is indeed part of ES6  it is unfortunately not yet supported in NodeJS by default  and has only very recently landed support in browsers   See browser compat table on MDN and this Node issue   From James M Snell s Update on ES6 Modules in Node js  February 2017       Work is in progress but it is going to take some time     We   re currently looking at around a year at least    Until support shows up natively  you ll have to continue using classic require statements   const express   require  express      If you really want to use new ES6 7 features in NodeJS  you can compile it using Babel  Here s an example server

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babel 7 proposal can you add dev dependencies   npm i -D  babel core  babel preset-env  babel register   and add a  babelrc in the root     presets               babel preset-env                targets              node    current                          and add to the  js file  require   babel register     or if you run it in the cli  you could use the require hook as -r  babel register  ex    node -r  babel register executeMyFileWithESModules js

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As of Node js v12  and this is probably fairly stable now  but still marked  experimental    you have a couple of options for using ESM  ECMAScript Modules  in Node js  for files  there s a third way for evaling strings   here s what the documentation says    The --experimental-modules flag can be used to enable support for ECMAScript modules  ES modules   Once enabled  Node js will treat the following as ES modules when passed to node as the initial input  or when referenced by import statements within ES module code    Files ending in  mjs    Files ending in  js  or extensionless files  when the nearest parent package json file contains a top-level field  type  with a value of  module     Strings passed in as an argument to --eval or --print  or piped to node via STDIN  with the flag --input-type module    Node js will treat as CommonJS all other forms of input  such as  js files where the nearest parent package json file contains no top-level  type  field  or string input without the flag --input-type  This behavior is to preserve backward compatibility  However  now that Node js supports both CommonJS and ES modules  it is best to be explicit whenever possible  Node js will treat the following as CommonJS when passed to node as the initial input  or when referenced by import statements within ES module code    Files ending in  cjs    Files ending in  js  or extensionless files  when the nearest parent package json file contains a top-level field  type  with a value of  commonjs     Strings passed in as an argument to --eval or --print  or piped to node via STDIN  with the flag --input-type commonjs

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When I was started with express always wanted a solution to use import instead require  const express   require  express       to  import express from  express    Many time go through this line - Unfortunately  Node js doesn t support ES6 s import yet   Now to help other I create new two solutions here   1  esm -  The brilliantly simple  babel-less  bundle-less ECMAScript module loader  let s make it work    yarn add esm   npm install esm   create start js or use your namespace   require   require  esm   module    options        Import the rest of our application   module exports   require    src server js       where server js is express server start file   Change in your package josn pass path of start js     scripts          start    node start js        start dev    nodemon start js           dependencies           esm     3 2 25           devDependencies          nodemon     1 19 2        2  Babel js -   This can be divide into 2 part   a  Solution 1 thanks to timonweb com  b  Solution 2  use Babel 6  older version of babel-preset-stage-3  6 0   create  babelrc file at your root folder         presets     env    stage-3       Install babel-preset-stage-3  yarn add babel-cli babel-polyfill babel-preset-env bable-preset-stage-3 nodemon --dev   Change in package json   scripts          start dev    nodemon --exec babel-node --   src index js        start    npm run build  amp  amp  node   build index js        build    npm run clean  amp  amp  babel src -d build -s --source-maps --copy-files        clean    rm -rf build  amp  amp  mkdir build      devDependencies           babel-cli     6 26 0         babel-polyfill     6 26 0         babel-preset-env     1 7 0         babel-preset-stage-3     6 24 1         nodemon     1 19 4       Start your server  yarn start   npm start   Oooh no we create new problem   regeneratorRuntime mark function  callee email  password      ReferenceError  regeneratorRuntime is not defined   This error only come when you use async await in your code   Then use polyfill that includes a custom regenerator runtime and core-js   add on top of index js   import  babel-polyfill    This allow you to use async await  use Babel 7  Need to upto date every thing in your project let start with babel 7  babelrc       presets      babel preset-env       Some change in package json   scripts         start dev    nodemon --exec babel-node --   src index js       start    npm run build  amp  amp  node   build index js       build    npm run clean  amp  amp  babel src -d build -s --source-maps --copy-files       clean    rm -rf build  amp  amp  mkdir build               devDependencies           babel cli     7 0 0         babel core     7 6 4         babel node     7 0 0         babel polyfill     7 0 0         babel preset-env     7 0 0        nodemon     1 19 4           and use import   babel polyfill  on start point  import   babel polyfill  import express from  express  const app   express      GET request app get      async  req  res         await operation   res send  hello world      app listen 4000       gt  console log   Server listening on port 400       Are you thinking why start dev   Seriously   It is good question if you are new  Every change you are boar with start server every time then use yarn start dev as development server every change restart server automatically for more on nodemon

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Simply install a higher version of Node  As till Node v10 es6 is not supported  You need to disable a few flags or use

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Error   SyntaxError  Unexpected token import or SyntaxError  Unexpected token export    Solution  Change all your imports as example  const express                 require  express    const webpack                 require  webpack    const path                    require  path    const config                  require     webpack config dev    const open                    require  open        And also change your export default   foo  to module exports   foo

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import statements are supported in the stable release of Node since version 14 x LTS  All you need to do is specify  quot type quot    quot module quot  in package json

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In my case it was looking after  babelrc file  and it should contain something like this         presets     es2015-node5    stage-3       plugins

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if you can use  babel   try to add build scripts in package json --presets es2015  as below  it make to precompile import code to es2015   build    babel server --out-dir build --presets es2015  amp  amp  webpack

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My project uses node v10 21 0  which still does not support ES6 import keyword  There are multiple ways to make node recognize import  one of them is to start node with node  --experimental-modules  index mjs  The mjs extension is already covered in one of the answers here   But  this way  you will not be able to use node specific keyword like require in your code  If there is need to use both nodejs s require keyword along with ES6 s import  then the way out is to use the esm npm package  After adding esm package as a dependency  node needs to be started with a special configuration like  node -r esm index js

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Unfortunately  Node js doesn t support ES6 s import yet   To accomplish what you re trying to do  import the Express module   this code should suffice  var express   require  express      Also  be sure you have Express installed by running    npm install express   See the Node js Docs for more information about learning Node js

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