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JavaScript Angular Basics Setting Up an Angular Application Your First Angular Application

Posted by jlampstack
jlampstack
23,932 Points

Lots of error messages after npm install

Everything seems to be working and I got the server running, but there were also tonnes of error messages after running npm install. This surely can't be healthy. I'm wondering what the protocol would be for this in a real life situation, and how it would be handled. These messages are overwhelming. Can anyone shed some light?

MY STEPS

  1. git clone https://hithub.com/treehouse-projects/photoblog.git
  2. cd photoblog
  3. npm install
  4. npm run serve

On npm install I get the following messages

$ npm install

> photoblog@ postinstall C:\xampp\htdocs\angular2-treehouse\photoblog
> npm run build


> photoblog@ build C:\xampp\htdocs\angular2-treehouse\photoblog
> webpack


[at-loader] Using typescript@2.1.4 from typescript and "tsconfig.json" from C:\xampp\htdocs\angular2-treehouse\photoblog\src\tsconfig.json.


[at-loader] Checking started in a separate process...

[at-loader] Ok, 0.569 sec.
Hash: c8cbe786d89bccdb5858
Version: webpack 1.14.0
Time: 59779ms
                                Asset       Size  Chunks             Chunk Names
          app.c8cbe786d89bccdb5858.js  177 bytes       0  [emitted]  app
    polyfills.c8cbe786d89bccdb5858.js     101 kB       1  [emitted]  polyfills
       vendor.c8cbe786d89bccdb5858.js     912 kB       2  [emitted]  vendor
                              app.css    1.31 kB       0  [emitted]  app
      app.c8cbe786d89bccdb5858.js.map    1.03 kB       0  [emitted]  app
                          app.css.map   84 bytes       0  [emitted]  app
polyfills.c8cbe786d89bccdb5858.js.map     772 kB       1  [emitted]  polyfills
   vendor.c8cbe786d89bccdb5858.js.map     6.6 MB       2  [emitted]  vendor
                           index.html  478 bytes          [emitted]
    + 662 hidden modules

WARNING in polyfills.c8cbe786d89bccdb5858.js from UglifyJs
Condition always true [../~/angular2-template-loader!./polyfills.ts:6,4]
Dropping unreachable code [../~/angular2-template-loader!./polyfills.ts:10,4]
Condition always true [../~/zone.js/dist/zone.js:9,0]
Non-strict equality against boolean: == false [../~/zone.js/dist/zone.js:1658,0]
Condition left of || always false [../~/zone.js/dist/zone.js:556,0]
Condition left of || always false [../~/zone.js/dist/zone.js:559,0]
Dropping unused variable frameParserStrategy [../~/zone.js/dist/zone.js:674,0]
Dropping unused function findAllExistingRegisteredTasks [../~/zone.js/dist/zone.js:964,0]
Side effects in initialization of unused variable Zone$1 [../~/zone.js/dist/zone.js:23,0]
Side effects in initialization of unused variable zoneAwareAddEventListener [../~/zone.js/dist/zone.js:1100,0]
Side effects in initialization of unused variable zoneAwareRemoveEventListener [../~/zone.js/dist/zone.js:1101,0]

WARNING in vendor.c8cbe786d89bccdb5858.js from UglifyJs
Condition always true [../~/@angular/core/bundles/core.umd.js:7,0]
Dropping unreachable code [../~/@angular/core/bundles/core.umd.js:430,0]
Declarations in unreachable code! [../~/@angular/core/bundles/core.umd.js:430,0]
Dropping unreachable code [../~/@angular/core/bundles/core.umd.js:467,0]
Declarations in unreachable code! [../~/@angular/core/bundles/core.umd.js:467,0]
Condition always true [../~/@angular/common/bundles/common.umd.js:7,0]
Dropping unreachable code [../~/@angular/common/bundles/common.umd.js:2807,0]
Declarations in unreachable code! [../~/@angular/common/bundles/common.umd.js:2807,0]
Side effects in initialization of unused variable WrappedError [../~/@angular/common/bundles/common.umd.js:2408,0]
Condition always true [../~/@angular/platform-browser/bundles/platform-browser.umd.js:7,0]
Condition always true [../~/@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js:7,0]
Condition always true [../~/@angular/compiler/bundles/compiler.umd.js:7,0]
Dropping unreachable code [../~/@angular/compiler/bundles/compiler.umd.js:7768,0]
Declarations in unreachable code! [../~/@angular/compiler/bundles/compiler.umd.js:7768,0]
Dropping unreachable code [../~/@angular/compiler/bundles/compiler.umd.js:7820,0]
Declarations in unreachable code! [../~/@angular/compiler/bundles/compiler.umd.js:7820,0]
Dropping unreachable code [../~/@angular/compiler/bundles/compiler.umd.js:7843,0]
Declarations in unreachable code! [../~/@angular/compiler/bundles/compiler.umd.js:7843,0]
Dropping unreachable code [../~/@angular/compiler/bundles/compiler.umd.js:17009,0]
Declarations in unreachable code! [../~/@angular/compiler/bundles/compiler.umd.js:17009,0]
Side effects in initialization of unused variable token [../~/@angular/compiler/bundles/compiler.umd.js:23004,27]
Side effects in initialization of unused variable parentNodeIndex [../~/@angular/compiler/bundles/compiler.umd.js:23902,35]
Non-strict equality against boolean: != true [../~/@angular/compiler/bundles/compiler.umd.js:1096,0]
Dropping unreachable code [../~/@angular/compiler/bundles/compiler.umd.js:8422,0]
Declarations in unreachable code! [../~/@angular/compiler/bundles/compiler.umd.js:8422,0]
Dropping unreachable code [../~/@angular/compiler/bundles/compiler.umd.js:8746,0]
Declarations in unreachable code! [../~/@angular/compiler/bundles/compiler.umd.js:8746,0]
Side effects in initialization of unused variable provider [../~/@angular/compiler/bundles/compiler.umd.js:25393,0]
Side effects in initialization of unused variable ngModuleByPipeOrDirective [../~/@angular/compiler/bundles/compiler.umd.js:27751,0]
Side effects in initialization of unused variable WrappedError [../~/@angular/compiler/bundles/compiler.umd.js:1641,0]
Side effects in initialization of unused variable INT_TYPE [../~/@angular/compiler/bundles/compiler.umd.js:14131,19]
Side effects in initialization of unused variable CATCH_ERROR_VAR [../~/@angular/compiler/bundles/compiler.umd.js:14863,19]
Side effects in initialization of unused variable CATCH_STACK_VAR [../~/@angular/compiler/bundles/compiler.umd.js:14864,19]
Side effects in initialization of unused variable CommentStmt [../~/@angular/compiler/bundles/compiler.umd.js:15118,0]
Side effects in initialization of unused variable NOT_THROW_ON_CHANGES [../~/@angular/compiler/bundles/compiler.umd.js:22800,19]
Child html-webpack-plugin for "index.html":
        + 1 hidden modules
Child extract-text-webpack-plugin:
        + 2 hidden modules
npm WARN photoblog@ No repository field.
npm WARN photoblog@ No license field.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.1.3 (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.1.3: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

up to date in 93.001s

5 Answers

james south
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
james south
Front End Web Development Techdegree Graduate 33,271 Points
james south
.a{fill-rule:evenodd;}techdegree seal-36
james south
Front End Web Development Techdegree Graduate 33,271 Points

these are all just warning messages. i'm no expert but i get warnings when i npm install stuff and so do the teachers in the treehouse videos so i ignore them like they do. if it works, it works.

jlampstack
jlampstack
23,932 Points

Thanks James for taking the time to reply. Good to know. I still have a feeling that this can lead to even more problematic bugs in the future, especially after running updates etc? Wouldn't this leave our program vulnerable to bigger problems down the road?

Again, I'm only a student, so what do i know. Just sharing my thoughts =)

Jacob Mishkin
Jacob Mishkin
23,117 Points
Jacob Mishkin
Jacob Mishkin
23,117 Points

Did this happen only when you types npm install? when you run your program are there errors? Lastly, are you using Windows preferred programs not Linux?

jlampstack
jlampstack
23,932 Points

Jacob Mishkin This happens only after npm install . I am using Windows 10.

The program works perfectly, just that i'm seeing these messages.

Jacob Mishkin
Jacob Mishkin
23,117 Points

What you are seeing are not errors, but rather warnings during the download process.

jlampstack
jlampstack
23,932 Points

Thank you Jacob Mishkin . Should I just ignore the errors? Are they irrelevant? Will they cause problems in future if ignored now?

Miguel López
Miguel López
7,055 Points
Miguel López
Miguel López
7,055 Points

Hi Jay.

It is very unlikely that this warnings will cause problems later.

This are just "comments" about what uglify is doing to your code during minification. As far as i know unreachable code are the statements that are placed in lines that never will be executed, like:

function f() {
  var x = 3;
  x += 4;
  return x;   // here the return statement exits the function immediately
  x -= 3;     // this line is unreachable and never will be executed, so uglify will drop it
}

This is what i understood at least.

Now if you ask me, why unreachable code is there?... well, i don't know.

Luke Pettway
Luke Pettway
16,593 Points
Luke Pettway
Luke Pettway
16,593 Points

As others have mentioned these are normal warnings. It's uglify letting you know that it is finding unreachable code so it is trimming it out. From the looks of it you are using an Angular 2 project, and I have seen those same errors before. It is a bit annoying to have that many warnings displayed, but that just means uglify is doing it's job. Here's a Github issue with someone else seeing the same thing https://github.com/webpack/webpack/issues/2352.

You should only ever see those warnings when you run npm run build because the Angular webpack build process runs uglify and thus throws warnings that unreachable code was found.

ervw3
ervw3
17,868 Points
ervw3
ervw3
17,868 Points

You spelled GitHub as Hithub, that's why you had an error.