From 487486ae66766c593bda64e147caf03cbcc40bdd Mon Sep 17 00:00:00 2001
From: Joey Perrott <josephperrott@gmail.com>
Date: Wed, 21 Jul 2021 14:52:48 -0700
Subject: [PATCH] refactor(@schematics/angular): automatically determine the
 version string to match latest Angular

Automatically determine the latest compatible Angular Framework version by using `~` matching
for the current minor version of @schematics/angular.
---
 .../angular/utility/latest-versions.ts         | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/packages/schematics/angular/utility/latest-versions.ts b/packages/schematics/angular/utility/latest-versions.ts
index 9e72bb148bab..58a08680b674 100644
--- a/packages/schematics/angular/utility/latest-versions.ts
+++ b/packages/schematics/angular/utility/latest-versions.ts
@@ -6,14 +6,30 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+/** Retrieve the minor version for the provided version string. */
+function getEarliestMinorVersion(version: string) {
+  const versionMatching = version.match(/^(\d+)\.(\d+)\.*/);
+
+  if (versionMatching === null) {
+    throw Error('Unable to determine the minor version for the provided version');
+  }
+  const [_, major, minor] = versionMatching;
+
+  return `${major}.${minor}.0`;
+}
+
 export const latestVersions = {
   // These versions should be kept up to date with latest Angular peer dependencies.
-  Angular: '~12.1.2',
   RxJs: '~6.6.0',
   ZoneJs: '~0.11.4',
   TypeScript: '~4.3.2',
   TsLib: '^2.2.0',
 
+  // As Angular CLI works with same minor versions of Angular Framework, a tilde match for the current
+  // Angular CLI minor version with earliest prerelease (appended with `-`) will match the latest
+  // Angular Framework minor.
+  Angular: `~${getEarliestMinorVersion(require('../package.json')['version'])}-`,
+
   // Since @angular-devkit/build-angular and @schematics/angular are always
   // published together from the same monorepo, and they are both
   // non-experimental, they will always have the same version.