feat(@angular/cli): use STDERR to report warnings

Author: hansl

packages/angular/cli/lib/init.ts

@@ -99,7 +99,7 @@ try {
     // Don't show warning colorised on `ng completion`
     if (process.argv[2] !== 'completion') {
         // eslint-disable-next-line no-console
-      console.log(warning);
+      console.error(warning);
     } else {
         // eslint-disable-next-line no-console
       console.error(warning);
@@ -141,6 +141,6 @@ cli({
     process.exit(exitCode);
   })
   .catch((err: Error) => {
-    console.log('Unknown error: ' + err.toString());
+    console.error('Unknown error: ' + err.toString());
     process.exit(127);
   });

packages/angular/cli/upgrade/version.ts

@@ -87,7 +87,7 @@ export class Version {
     const rxjsVersion = new Version(rxjsPkgJson['version']);
 
     if (angularVersion.isLocal()) {
-      console.warn(terminal.yellow('Using a local version of angular. Proceeding with care...'));
+      console.error(terminal.yellow('Using a local version of angular. Proceeding with care...'));
 
       return;
     }
@@ -175,7 +175,7 @@ export class Version {
 
     if (currentCombo && !satisfies(tsVersion, currentCombo.typescript)) {
       // First line of warning looks weird being split in two, disable tslint for it.
-      console.log((terminal.yellow('\n' + tags.stripIndent`
+      console.error((terminal.yellow('\n' + tags.stripIndent`
         @angular/compiler-cli@${compilerVersion} requires typescript@'${
         currentCombo.typescript}' but ${tsVersion} was found instead.
         Using this version can result in undefined behaviour and difficult to debug problems.

packages/angular/cli/utilities/check-package-manager.ts

@@ -27,16 +27,16 @@ export function checkYarnOrCNPM() {
       .then((data: Array<boolean>) => {
         const [isYarnInstalled, isCNPMInstalled] = data;
         if (isYarnInstalled && isCNPMInstalled) {
-          console.log(terminal.yellow('You can `ng config -g cli.packageManager yarn` '
+          console.error(terminal.yellow('You can `ng config -g cli.packageManager yarn` '
             + 'or `ng config -g cli.packageManager cnpm`.'));
         } else if (isYarnInstalled) {
-          console.log(terminal.yellow('You can `ng config -g cli.packageManager yarn`.'));
+          console.error(terminal.yellow('You can `ng config -g cli.packageManager yarn`.'));
         } else if (isCNPMInstalled) {
-          console.log(terminal.yellow('You can `ng config -g cli.packageManager cnpm`.'));
+          console.error(terminal.yellow('You can `ng config -g cli.packageManager cnpm`.'));
         } else  {
           if (packageManager !== 'default' && packageManager !== 'npm') {
-            console.log(terminal.yellow(`Seems that ${packageManager} is not installed.`));
-            console.log(terminal.yellow('You can `ng config -g cli.packageManager npm`.'));
+            console.error(terminal.yellow(`Seems that ${packageManager} is not installed.`));
+            console.error(terminal.yellow('You can `ng config -g cli.packageManager npm`.'));
           }
         }
       });