yarn xxx 和yarn run xxx

//package.json
"scripts": {
    "dev": "vue-cli-service serve --open",
    "build:prod": "vue-cli-service build",
    "build": "vue-cli-service build",
  },

yarn xxx 是运行package.json里scripts下的指令，比如yarn dev等同于vue-cli-service serve --open;

It’s also possible to leave out the run in this command, each script can be executed with its name

即yarn run xxx等同于yarn xxx

参考：yarn run