From b3d6d500bea6b3718e09cf986a1986fc57de9d09 Mon Sep 17 00:00:00 2001 From: Kapunahele Wong Date: Tue, 22 Oct 2019 14:14:53 -0400 Subject: [PATCH] docs: add ngcc postinstall migration doc (#33328) PR Close #33328 --- .github/CODEOWNERS | 1 + aio/content/guide/deprecations.md | 5 ++ aio/content/guide/migration-ngcc.md | 79 +++++++++++++++++++++++++++++ 3 files changed, 85 insertions(+) create mode 100644 aio/content/guide/migration-ngcc.md diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS index 2b08884362..86c818b5e4 100644 --- a/.github/CODEOWNERS +++ b/.github/CODEOWNERS @@ -887,6 +887,7 @@ testing/** @angular/fw-test /aio/content/guide/migration-injectable.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes /aio/content/guide/migration-localize.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes /aio/content/guide/migration-module-with-providers.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes +/aio/content/guide/migration-ngcc.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes # ================================================ diff --git a/aio/content/guide/deprecations.md b/aio/content/guide/deprecations.md index c536e19a3e..6e4693b6b2 100644 --- a/aio/content/guide/deprecations.md +++ b/aio/content/guide/deprecations.md @@ -366,6 +366,11 @@ See the [dedicated migration guide for adding missing `@Injectable` decorators]( ### Migrating `ModuleWithProviders` See the [dedicated migration guide for `ModuleWithProviders`](guide/migration-module-with-providers). +{@a ngcc-migration} +### Migrating to `ngcc` npm `postinstall` script + + See the [dedicated migration guide for `ngcc` npm `postinstall` script](guide/migration-ngcc). + {@a removed} diff --git a/aio/content/guide/migration-ngcc.md b/aio/content/guide/migration-ngcc.md new file mode 100644 index 0000000000..8535b0e96b --- /dev/null +++ b/aio/content/guide/migration-ngcc.md @@ -0,0 +1,79 @@ +# Migration to `ngcc` npm `postinstall` script + +## What does this schematic do? + +This schematic adds an [Angular compatibility compiler](guide/ngcc), or `ngcc`, invocation to npm/yarn's `postinstall` script in the `package.json` of an Angular CLI workspace. +This script is invoked after each execution of `npm install` and modifies `node_modules` by converting any found Angular libraries to a format that is compatible with Angular version 9. + +An example diff might look like the following: + +**Before:** + +```json + "scripts": { + "ng": "ng", + "start": "ng serve", + "build": "ng build", + "test": "ng test", + "lint": "ng lint", + "e2e": "ng e2e" + }, +``` + +**After:** + +```json + "scripts": { + "ng": "ng", + "start": "ng serve", + "build": "ng build", + "test": "ng test", + "lint": "ng lint", + "e2e": "ng e2e", + "postinstall": "ngcc --properties es2015 browser module main --first-only --create-ivy-entry-points" + }, +``` + +If the `package.json` already contains a `postinstall` script, then the `ngcc` invocation will be prepended to the current command: + +**Before:** +```json + "scripts": { + ... + "postinstall": "some-command" + }, +``` + +**After:** +```json + "scripts": { + ... + "postinstall": "ngcc --properties es2015 browser module main --first-only --create-ivy-entry-points && some-command" + }, +``` + + +## Why is this migration necessary? + +This migration is a build performance optimization that enables `ngcc` to parallelize the compilation of npm libraries. +An application build performed via CLI's `ng build` should succeed regardless of this `postinstall` script being installed, because the CLI has `ngcc` built-in. +However, this built-in `ngcc` can't parallelize the compilation of multiple libraries, and therefore often takes considerably longer to run. + + +## Can I customize the `ngcc` options in the `postinstall` script? + +By default the `postinstall` script invokes `ngcc` with options to compile only the most commonly needed library formats. +For some projects, especially those that depend on the CommonJS distribution of Angular (for example, Angular Universal apps), it might be beneficial to modify the `postinstall` script to also compile the CommonJS distribution of the library: + +```json + "scripts": { + ... + "postinstall": "ngcc --properties es2015 browser module main --first-only --create-ivy-entry-points && ngcc --properties main --create-ivy-entry-points" + }, +``` + +For the full set of options run `npx ngcc --help` or `yarn ngcc --help`. + +## Will libraries compiled with `ngcc` still be compatible with Angular version 8? + +Yes, the migration causes `ngcc` to be invoked with the `--create-ivy-entry-points` flag, which ensures that the `ngcc` compilation is non-destructive, so the same `node_modules` can be used with Angular version 8 and version 9.