angular-cn/packages/compiler-cli/ngcc
Paul Gschwendtner 6b468f9b2e fix(ngcc): libraries using spread in object literals cannot be processed (#34661)
Consider a library that uses a shared constant for host bindings. e.g.

```ts
export const BASE_BINDINGS= {
  '[class.mat-themed]': '_isThemed',
}

----

@Directive({
  host: {...BASE_BINDINGS, '(click)': '...'}
})
export class Dir1 {}

@Directive({
  host: {...BASE_BINDINGS, '(click)': '...'}
})
export class Dir2 {}
```

Previously when these components were shipped as part of the
library to NPM, consumers were able to consume `Dir1` and `Dir2`.
No errors showed up.

Now with Ivy, when ngcc tries to process the library, an error
will be thrown. The error is stating that the host bindings should
be an object (which they obviously are). This happens because
TypeScript transforms the object spread to individual
`Object.assign` calls (for compatibility).

The partial evaluator used by the `@Directive` annotation handler
is unable to process this expression because there is no
integrated support for `Object.assign`. In View Engine, this was
not a problem because the `metadata.json` files from the library
were used to compute the host bindings.

Fixes #34659

PR Close #34661
2020-01-23 10:29:57 -08:00
..
src fix(ngcc): libraries using spread in object literals cannot be processed (#34661) 2020-01-23 10:29:57 -08:00
test fix(ngcc): libraries using spread in object literals cannot be processed (#34661) 2020-01-23 10:29:57 -08:00
BUILD.bazel perf(ivy): reuse prior analysis work during incremental builds (#34288) 2019-12-12 13:11:45 -08:00
README.md
index.ts refactor(ngcc): add support for asynchronous execution (#32427) 2019-09-09 15:55:13 -04:00
main-ivy-ngcc.ts fix(ngcc): rename the executable from `ivy-ngcc` to `ngcc` (#33140) 2019-10-14 16:29:14 +00:00
main-ngcc.ts fix(ngcc): render legacy i18n message ids by default (#34135) 2019-12-03 10:15:53 -08:00

README.md

Angular Compatibility Compiler (ngcc)

This compiler will convert node_modules compiled with ngc, into node_modules which appear to have been compiled with ngtsc.

This conversion will allow such "legacy" packages to be used by the Ivy rendering engine.

Building

The project is built using Bazel:

yarn bazel build //packages/compiler-cli/ngcc

Unit Testing

The unit tests are built and run using Bazel:

yarn bazel test //packages/compiler-cli/ngcc/test

Integration Testing

There are tests that check the behavior of the overall executable:

yarn bazel test //packages/compiler-cli/ngcc/test:integration