Can't use aot with a let var in custom scripts

[Jonathan002]

Versions

@angular/cdk: 5.0.0-rc0
@angular/cli: 1.5.2
@angular/material: 5.0.0-rc0
@angular/platform-server: 4.4.6
@angular/tsc-wrapped: 4.4.6
@angular-devkit/build-optimizer: 0.0.33
@angular-devkit/core: 0.0.20
@angular-devkit/schematics: 0.0.35
@ngtools/json-schema: 1.1.0
@ngtools/webpack: 1.8.2
@schematics/angular: 0.1.2
typescript: 2.4.2
webpack: 3.8.1

Repro steps

• Create New Angular CLI Project
• Create a script file in src and add it to angular.cli
• Create a let var in custom script -
  /src/custom-script.js - let object = {}
• Try to compile the project with --aot and --prod flag. npm run build --aot --prod

Observed behavior

<!-- Normally this includes a stack trace and some more information. -->

You will get the error:

(node:22021) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

and no dist folder will be created.

Desired behavior

Successful aot build compilation and creation of a dist folder for the project.

Mention any other details that might be useful (optional)

I've created a repository with the custom script problem setup in .angular-cli.json.

Link: https://github.com/Jonathan002/angular-cli-broken-aot-demo

[filipesilva]

Heya @Jonathan002, thanks for opening this and including a repro. I think I know why it happens: we Uglify scripts with an older version of Uglify that doesn't support ES6 constructs such as let. It's a matter of updating https://github.com/hxlniada/webpack-concat-plugin to use the newer Uglify-ES.

[tomastrajan]

I'll do it, if I understand correctly it's about creating PR with version bump of uglify-js for webpack-concat-plugin repo and then owner has to release it and then we bump version used by @angular/cli right @filipesilva ?

[tomastrajan]

Ok so I created a PR in the webpack-concat-plugin which solves the issue when testing against the provided reproduction repo. Also tried to run Angular CLI tests with the updated plugin locally and all worked fine.

[filipesilva]

@tomastrajan thanks for taking this on. I also pinged the library owner there about this change.

[tomastrajan]

Ok so the webpack-concat-plugin 2.0.0 was released with uglify-es! I'll create a PR with the version bump.

[tomastrajan]

Ok, so i created the PR, hope it's all good @filipesilva .

[tomastrajan]

This seems to be solved by PR#8849 .