为什么angular library的build不能将assets静态资源打包进去（转）

Versions

Angular CLI: 6.0.7
Node: 9.3.0
OS: darwin x64
Angular: 6.0.3
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

Package                            Version
------------------------------------------------------------
@angular-devkit/architect          0.6.7
@angular-devkit/build-angular      0.6.7
@angular-devkit/build-ng-packagr   0.6.7
@angular-devkit/build-optimizer    0.6.7
@angular-devkit/core               0.6.7
@angular-devkit/schematics         0.6.7
@angular/cdk                       6.2.0
@angular/cli                       6.0.7
@angular/material                  6.2.0
@ngtools/json-schema               1.1.0
@ngtools/webpack                   6.0.7
@schematics/angular                0.6.7
@schematics/update                 0.6.7
ng-packagr                         3.0.0
rxjs                               6.2.0
typescript                         2.7.2
webpack                            4.8.3

Repro steps

• Create a library @acme/lib1 using ng generate library @acme/lib1
• Create assets folder under projects/acme/lib1/assets and add images
• Add a "projects" -> "@acme/lib1" -> "architect" -> "build" -> "options" -> "assets" key to the library's config within angular.json file.
• Build library using ng build @acme/lib1
• Fail error should show and none of the assets will be copied to dist folder.

Observed behavior

Upon building & packaging an Angular 6 library e.g. @acme/lib1 using ng build @acme/lib1, the Angular CLI does not copy the library's assets into the dist/acme/lib1/assets folder. This happens also when using the --prod flag.

The CLI seems to only support copying the root app's assets but not library specific assets.
When trying to add "assets": ["src/assets"] to project @acme/lib1 within angular.json, the following error appears in the command line:

Schema validation failed with the following errors: Data path "" should NOT have additional properties(assets).

When creating the following custom rule to copying the files on ng build:

 "assets": [
    "src/favicon.ico",
    "src/assets",
     { "glob": "**/*", "input": "src/assets", "output": "../acme/lib1/assets/" }
],

I get the following error:

An asset cannot be written to a location outside of the output path.

While it is possible to work around this issue using other command line tools/scripts, it will be more consistent to add support for library's assets copy as well.

Desired behavior

Use Case
Very often libraries include image files, icons, css files and other static files which are needed to be distrubted with the package.

What would like to see implemented?
Add ability to define a library specific assets property within angular.json.
Example -

"@acme/lib1": {
      "root": "projects/acme/lib1",
      "sourceRoot": "projects/acme/lib1/src",
      "projectType": "library",
      "prefix": "lib",
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-ng-packagr:build",
          "options": {
            "tsConfig": "projects/acme/lib1/tsconfig.lib.json",
            "project": "projects/acme/lib1r/ng-package.json",
            "assets": [ // <--------- this is currently not supported
              "src/assets"
            ]
          },
  ...}

What did you expect to see?
Project's specific assets should be copied from projects/acme/lib1/src/assets into dist/acme/lib1/assets.

Mention any other details that might be useful (optional)

原文地址：https://github.com/angular/angular-cli/issues/11071