95c729f5d1
This commit adds support in the Angular monorepo and in the Angular compiler(s) for TypeScript 3.8. All packages can now compile with TS 3.8. For most of the repo, only a handful few typings adjustments were needed: * TS 3.8 has a new `CustomElementConstructor` DOM type, which enforces a zero-argument constructor. The `NgElementConstructor` type previously declared a required `injector` argument despite the fact that its implementation allowed `injector` to be optional. The interface type was updated to reflect the optionality of the argument. * Certain error messages were changed, and expectations in tests were updated as a result. * tsserver (part of language server) now returns performance information in responses, so test expectations were changed to only assert on the actual body content of responses. For compiler-cli and schematics (which use the TypeScript AST) a major breaking change was the introduction of the export form: ```typescript export * as foo from 'bar'; ``` This is a `ts.NamespaceExport`, and the `exportClause` of a `ts.ExportDeclaration` can now take this type as well as `ts.NamedExports`. This broke a lot of places where `exportClause` was assumed to be `ts.NamedExports`. For the most part these breakages were in cases where it is not necessary to handle the new `ts.NamedExports` anyway. ngtsc's design uses the `ts.TypeChecker` APIs to understand syntax and so automatically supports the new form of exports. The View Engine compiler on the other hand extracts TS structures into metadata.json files, and that format was not designed for namespaced exports. As a result it will take a nontrivial amount of work if we want to support such exports in View Engine. For now, these new exports are not accounted for in metadata.json, and so using them in "folded" Angular expressions will result in errors (probably claiming that the referenced exported namespace doesn't exist). Care was taken to only use TS APIs which are present in 3.7/3.6, as Angular needs to remain compatible with these for the time being. This commit does not update angular.io. PR Close #35864
Deals with the creation of generated factory files.
Generated factory files create a catch-22 in ngtsc. Their contents depends on static analysis of the current program, yet they're also importable from the current program. This importability gives rise to the requirement that the contents of the generated file must be known before program creation, so that imports of it are valid. However, until the program is created, the analysis to determine the contents of the generated file cannot take place.
ngc used to get away with this because the analysis phase did not depend on program creation but on the metadata collection / global analysis process.
ngtsc is forced to take a different approach. A lightweight analysis pipeline which does not rely on the ts.TypeChecker (and thus can run before the program is created) is used to estimate the contents of a generated file, in a way that allows the program to be created. A transformer then operates on this estimated file during emit and replaces the estimated contents with accurate information.
It is important that this estimate be an overestimate, as type-checking will always be run against the estimated file, and must succeed in every case where it would have succeeded with accurate info.
This directory contains the utilities for generating, updating, and incorporating these factory files into a ts.Program.