fix: pause & resume spinners elegantly

Author: haoqunjiang

packages/@vue/cli-service/lib/config/css.js

@@ -1,7 +1,7 @@
 const fs = require('fs')
 const path = require('path')
 const semver = require('semver')
-const { warn } = require('@vue/cli-shared-utils')
+const { warn, pauseSpinner, resumeSpinner } = require('@vue/cli-shared-utils')
 
 const findExisting = (context, files) => {
   for (const file of files) {
@@ -22,7 +22,9 @@ module.exports = (api, rootOptions) => {
       sassLoaderVersion = semver.major(require('sass-loader/package.json').version)
     } catch (e) {}
     if (sassLoaderVersion < 8) {
+      pauseSpinner()
       warn('sass-loader v8 is out, please consider upgrading your sass-loader version.')
+      resumeSpinner()
     }
 
     const defaultSassLoaderOptions = {}

packages/@vue/cli-shared-utils/lib/spinner.js

@@ -3,6 +3,7 @@ const chalk = require('chalk')
 
 const spinner = ora()
 let lastMsg = null
+let isPaused = false
 
 exports.logWithSpinner = (symbol, msg) => {
   if (!msg) {
@@ -36,11 +37,17 @@ exports.stopSpinner = (persist) => {
 }
 
 exports.pauseSpinner = () => {
-  spinner.stop()
+  if (spinner.isSpinning) {
+    spinner.stop()
+    isPaused = true
+  }
 }
 
 exports.resumeSpinner = () => {
-  spinner.start()
+  if (isPaused) {
+    spinner.start()
+    isPaused = false
+  }
 }
 
 exports.failSpinner = (text) => {