How to use Typescript with native ES6 Promises

Question

I m a complete beginner to Typescript and am wondering if it s possible to use ES6 promises in Typescript and what I would have to do to get them to work  I m running node 0 11 14 and am getting an error during compilation  Cannot find name  Promise

User · Answer

As of TypeScript 2 0 you can include typings for native promises by including the following in your tsconfig json   compilerOptions          lib     es5    es2015 promise       This will include the promise declarations that comes with TypeScript without having to set the target to ES6

User · Answer

The current lib d ts doesn t have promises in it defined so you need a extra definition file for it that is why you are getting compilation errors   You could for example use  like  elclanrs says  use the es6-promise package with the definition file from DefinitelyTyped  es6-promise definition  You can then use it like this   var p   new Promise lt string gt   resolve  reject    gt         resolve  a string           edit You can use it without a definition when targeting ES6  with the TypeScript compiler  - Note you still require the Promise to exists in the runtime ofcourse  so it won t work in old browsers     Add Edit the following to your tsconfig json     compilerOptions          target    ES6      edit 2 When TypeScript 2 0 will come out things will change a bit  though above still works  but definition files can be installed directly with npm like below   npm install --save  types es6-promise - source  edit3 Updating answer with more info for using the types   Create a package json file with only     as the content  if you don t have a package json already  Call npm install --save  types es6-promise and tsc --init  The first npm install command will change your package json to include the es6-promise as a dependency  tsc --init will create a tsconfig json file for you   You can now use the promise in your typescript file var x  Promise lt any gt    Execute tsc -p   to compile your project  You should have no errors

User · Answer

Using native ES6 Promises with Typescript in Visual Studio 2015   Node js tools 1 2  No npm install required as ES6 Promises is native   Node js project -  Properties -  Typescript Build tab ECMAScript version   ECMAScript6  import http   require  http    import fs   require  fs     function findFolderAsync directory   string   Promise lt string gt         let p   new Promise lt string gt  function  resolve  reject             fs stat directory  function  err  stats                   Check if error defined and the error code is  not exists              if  err  amp  amp  err code      ENOENT                     reject  Directory does not exist                              else                   resolve  Directory exists                                           return p     findFolderAsync  myFolder   then       function  msg   string            console log  Promise resolved as     msg               function  msg   string            console log  Promise rejected as     msg

User · Answer

A  If using  target    es5  and TypeScript version below 2 0   typings install es6-promise --save --global --source dt   B  If using  target    es5  and TypeScript version 2 0 or higer    compilerOptions          lib     es5    es2015 promise       C  If using  target    es6   there s no need to do anything

User · Answer

This the most recent way to do this  the above answer is outdated   typings install --global es6-promise

User · Answer

I had to downgrade  types core-js to 9 36 to get it to work with  target    es5  set in my tsconfig     types core-js    0 9 36

User · Answer

If you use node js 0 12 or above   typescript 1 4 or above  just add compiler options like   tsc a ts --target es6 --module commonjs   More info  https   github com Microsoft TypeScript wiki Compiler-Options  If you use tsconfig json  then like this          compilerOptions              module    commonjs            target    es6            More info  https   github com Microsoft TypeScript wiki tsconfig json

User · Answer

Alternative  1  Use the target and lib compiler options to compile directly to es5 without needing to install the es6-shim   Tested with TypeScript 2 1 4   In the lib section  use either es2016 or es2015 promise       tsconfig json        compilerOptions              target    es5            lib                  es2015 promise                dom                        include              src      ts              exclude              node modules            Alternative  2  Use NPM to install the es6-shim from the types organization   npm install  types es6-shim --save-dev   Alternative  3  Before TypeScript 2 0  use typings to install the es6-shim globally from DefinitelyTyped   npm install typings --global --save-dev typings install dt es6-shim --global --save-dev   The typings option uses npm to install typings globally and then uses typings to install the shim  The dt  prefix means to download the shim from DefinitelyTyped  The --global option means that the shim s types will be available throughout the project   See also  https   github com Microsoft TypeScript issues 7788 - Cannot find name  Promise   amp  Cannot find name  require

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