Recent optimizations to ngcc have significantly reduced the total time it takes to process `node_modules`, to such extend that sharding across multiple processes has become less effective. Previously, running ngcc asynchronously would allow for up to 8 workers to be allocated, however these workers have to repeat work that could otherwise be shared. Because ngcc is now able to reuse more shared computations, the overhead of multiple workers is increased and therefore becomes less effective. As an additional benefit, having fewer workers requires less memory and less startup time. To give an idea, using the following test setup: ```bash npx @angular/cli new perf-test cd perf-test yarn ng add @angular/material ./node_modules/.bin/ngcc --properties es2015 module main \ --first-only --create-ivy-entry-points ``` We observe the following figures on CI: | | 10.1.1 | PR #38840 | | ----------------- | --------- | --------- | | Sync | 85s | 25s | | Async (8 workers) | 22s | 16s | | Async (4 workers) | - | 11s | In addition to changing the default number of workers, ngcc will now use the environment variable `NGCC_MAX_WORKERS` that may be configured to either reduce or increase the number of workers. PR Close #38840
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