Merge configuration no longer accepts custom labels, in order to achieve consistent labelling as specified in the Angular versioning/branching/labelling spec.
The browser targets provided by `browserslist` have several differences than what `esbuild` expects for the Safari browsers. The first is that the iOS Safari is named `ios_saf` within browserslist and `ios` by esbuild. The former is now converted to the later when generating the target list for esbuild. The second difference is that `browserslist` supports a `TP` (Technology Preview) version for Safari but esbuild expects a numeric value for all versions. Since a TP version of Safari is assumed to be the latest unreleased version and as a result supports all currently known features, a high version number (999) is used as a replacement when generating the target list for esbuild.
Previously, browserslist configuration was not added in library projects. This in some cases caused a large number of CSS prefixes to be included in components stylesheets
BREAKING CHANGE:
The dev-server now uses WebSockets to communicate changes to the browser during HMR and live-reloaded. If during your development you are using a proxy you will need to enable proxying of WebSockets.
BREAKING CHANGE:
Support for `webpack-dev-server` version 3 has been removed. For more information about the migration please see: https://github.com/webpack/webpack-dev-server/blob/master/migration-v4.md
Note: this change only affects users depending on `@angular-devkit/build-webpack` directly.
To support the eventual migration of the CLI to ESM, the CLI commandline tool is now bootstrapped by dynamically importing the main initialization code. This is done to allow the main bin file (`ng`) to remain CommonJS so that older versions of Node.js can be checked and validated prior to the execution of the CLI. This separate bootstrap file is needed to allow the use of a dynamic import expression without crashing older versions of Node.js that do not support dynamic import expressions and would otherwise throw a syntax error. This bootstrap file is required from the main bin file only after the Node.js version is determined to be in the supported range. The use of the dynamic import expression allows CommonJS code to execute either CommonJS or ESM code.
rules_nodejs 4 requires that a package_name property be specified within a ts_library rule for the output to be linked into the package repository. Failing to add the property can cause test failures due to unresolved packages.
Much like the framework packages, the VERSION property will eventually be set via build-time stamping but the necessary build infrastructure is not yet in place. Until then, the global require usage has been replaced with a file read and JSON parse which provides the equivalent required behavior.
To support the eventual conversion of the `@angular/cli` package to ESM, the usage of the global require function must be removed as it is not supported in ESM code. Node.js does have the facility to create custom require functions that can be used when the need to synchronously load a file at runtime is required. Such cases have now been converted to use custom require functions where appropriate.
The `no-useless-escape` eslint rule has now been enabled which removes unneeded characters and complexity from string literals and regular expressions. All files that were in violation of this rule have also been corrected.
The internal TypeScript path mapping Webpack resolver plugin is used to adjust module resolution during builds via the TypeScript configuration `paths` option. Prior to a build, the `paths` option is now preprocessed to limit the amount of analysis that is needed within each individual module resolution attempt during a build. Since module resolution attempts can occur frequently during a build, this change offers the potential to reduce the total cost of module resolution especially for applications with a large amount of configured path mappings.
This migration updates libraries to be published in partial mode instead of view engine. Also, it removed deprecated options from ng-packagr configuration.
