JS, Browserify: function not defined

Question

I have files as represented:

-js/
    - calc.js
    - tool.js
-index.html

calc.js is a node module of following structure:

module.exports = {
   calculate: function() {...},
   getPrecision: function() {...}
}

and tool.js use require and adds some functions, like that:

const fpcalc = require('./fpcalc');

function changeState() {
//some code using fpcalc
}

I used Browserify to generate bundle.js and added that as script src. One of my buttons on HTML page is using onclick=changeState() . After clicking I'm getting

ReferenceError: changeState is not defined
at HTMLAnchorElement.onclick

Why is that? Is there any other way to make it work?

Answer 1

The function "changeState" is not exported in your tool.js. That means it is only visible inside your bundle.js, but not outside.

Have a look at this: https://makerlog.org/posts/creating-js-library-builds-with-browserify-and-other-npm-modules

It shows you how to expose your code to the global namespace in javascript.

Answer 2

Here's a very simple way to make it work like you want.

const fpcalc = require('./fpcalc');

window.changeState = () => {
    //some code using fpcalc
}

Answer 3

I have same error, here is my working example.

mac, browserify https://github.com/perliedman/reproject

            1) must use sudo install globally
                sudo npm install -g brwoserify

                 https://github.com/perliedman/reproject
                 sudo npm install reproject    // install locally is fine

                 must manually create 'dist' folder for later output file use

              2) must use --s expose global variable function 'reproject' and or 'toWgs84' you will use later in browser js.
                    without --s , will get 'reproject' undefined error . https://makerlog.org/posts/creating-js-library-builds-with-browserify-and-other-npm-modules
                    browserify --help will list all options.  -o means output file directory

                 browserify node_modules/reproject/index.js --s reproject -o node_modules/reproject/dist/reproject.js

html script tag include your above dist/reproject.js

now, you will not get 'reproejct' undefined error

         return reproject(_geometry_, ___from_projection, proj4.WGS84, crss)