vue.js：node_modules/_babel-runtime@6.26.0@babel-runtime/core-js/object/assign.js

{
  "dependencies": {
    "element-ui": "2.15.1",
    "vue": "2.6.10",
  },
  "devDependencies": {
    "@vue/cli": "4.5.19",
    "@vue/cli-service-global": "4.5.19"
  }
}

$ npx vue serve

ERROR  Failed to compile with 3 errors                                      2:32:02 PM
These dependencies were not found:
* core-js/library/fn/object/assign 
in ./node_modules/_babel-runtime@6.26.0@babel-runtime/core-js/object/assign.js
* core-js/library/fn/symbol 
in ./node_modules/_babel-runtime@6.26.0@babel-runtime/core-js/symbol.js
* core-js/library/fn/symbol/iterator 
in ./node_modules/_babel-runtime@6.26.0@babel-runtime/core-js/symbol/iterator.js
To install them, you can run: npm install --save 
core-js/library/fn/object/assign 
core-js/library/fn/symbol 
core-js/library/fn/symbol/iterator

npm install core-js@3 --save
npm install async-validator@1.11.5 --save
npm i -D babel-plugin-component

{
  "presets": [
    [
      "@babel/preset-env", 
      {
        "useBuiltIns": "usage",
        "corejs": 3 
      }
    ]
  ],
  "plugins": [
    [ "component",
      {
      "libraryName": "element-ui",
      "styleLibraryName": "theme-chalk"
      }
      ]
  ] 
}