ES6 export default with multiple functions referring to each other

Question

in es6 there you can define a module of functions like this  export default       foo     console log  foo           bar     console log  bar          baz     foo    bar         the above seems to be valid code  but if I call baz   it throws an error    ReferenceError  foo is not defined  How do you call foo from another function  in this case baz  Edit  Here s the code that actually doesn t work  I have simplified the code so it s only the core as needed  const tokenManager        revokeToken headers                     expireToken headers                   verifyToken req  res  next        jwt verify       gt          if  err            expireToken req headers                        export default tokenManager    and the error is  expireToken req headers             ReferenceError  expireToken is not defined   Edit 2  I just tried adding tokenManager before expireToken and it finally works

User · Answer

One alternative is to change up your module. Generally if you are exporting an object with a bunch of functions on it, it's easier to export a bunch of named functions, e.g.

export function foo() { console.log('foo') }, 
export function bar() { console.log('bar') },
export function baz() { foo(); bar() }

In this case you are export all of the functions with names, so you could do

import * as fns from './foo';

to get an object with properties for each function instead of the import you'd use for your first example:

import fns from './foo';

User · Answer

The export default       construction is just a shortcut for something like this   const funcs         foo     console log  foo           bar     console log  bar          baz     foo    bar        export default funcs   It must become obvious now that there are no foo  bar or baz functions in the module s scope  But there is an object named funcs  though in reality it has no name  that contains these functions as its properties and which will become the module s default export   So  to fix your code  re-write it without using the shortcut and refer to foo and bar as properties of funcs   const funcs         foo     console log  foo           bar     console log  bar          baz     funcs foo    funcs bar        here is the fix    export default funcs   Another option is to use this keyword to refer to funcs object without having to declare it explicitly  as  pawel has pointed out   Yet another option  and the one which I generally prefer  is to declare these functions in the module scope  This allows to refer to them directly   function foo     console log  foo     function bar     console log  bar     function baz     foo    bar      export default  foo  bar  baz    And if you want the convenience of default export and ability to import items individually  you can also export all functions individually      util js  export function foo     console log  foo     export function bar     console log  bar     export function baz     foo    bar      export default  foo  bar  baz      a js  using default export  import util from    util  util foo       b js  using named exports  import  bar  from    util  bar     Or  as  loganfsmyth suggested  you can do without default export and just use import     as  util  from     util  to get all named exports in one object

User · Answer

tl dr  baz     this foo    this bar      In ES2015 this construct   var obj         foo     console log  foo         is equal to this ES5 code   var obj         foo   function foo     console log  foo         exports default      is like creating an object  your default export translates to ES5 code like this   exports  default           foo  function foo             console log  foo               bar  function bar             console log  bar               baz  function baz             foo   bar               now it s kind of obvious  I hope  that baz tries to call foo and bar defined somewhere in the outer scope  which are undefined  But this foo and this bar will resolve to the keys defined in exports  default   object  So the default export referencing its own methods shold look like this   export default       foo     console log  foo           bar     console log  bar          baz     this foo    this bar         See babel repl transpiled code

[javascript] ES6 export default with multiple functions referring to each other

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