1module.exports = function(api) {
 2  var validEnv = ['development', 'test', 'production']
 3  var currentEnv = api.env()
 4  var isDevelopmentEnv = api.env('development')
 5  var isProductionEnv = api.env('production')
 6  var isTestEnv = api.env('test')
 7
 8  if (!validEnv.includes(currentEnv)) {
 9    throw new Error(
10      'Please specify a valid `NODE_ENV` or ' +
11        '`BABEL_ENV` environment variables. Valid values are "development", ' +
12        '"test", and "production". Instead, received: ' +
13        JSON.stringify(currentEnv) +
14        '.'
15    )
16  }
17
18  return {
19    presets: [
20      isTestEnv && [
21        '@babel/preset-env',
22        {
23          targets: {
24            node: 'current'
25          }
26        }
27      ],
28      (isProductionEnv || isDevelopmentEnv) && [
29        '@babel/preset-env',
30        {
31          forceAllTransforms: true,
32          useBuiltIns: 'entry',
33          corejs: 3,
34          modules: false,
35          exclude: ['transform-typeof-symbol']
36        }
37      ]
38    ].filter(Boolean),
39    plugins: [
40      'babel-plugin-macros',
41      '@babel/plugin-syntax-dynamic-import',
42      isTestEnv && 'babel-plugin-dynamic-import-node',
43      '@babel/plugin-transform-destructuring',
44      [
45        '@babel/plugin-proposal-class-properties',
46        {
47          loose: true
48        }
49      ],
50      [
51        '@babel/plugin-proposal-object-rest-spread',
52        {
53          useBuiltIns: true
54        }
55      ],
56      [
57        '@babel/plugin-transform-runtime',
58        {
59          helpers: false
60        }
61      ],
62      [
63        '@babel/plugin-transform-regenerator',
64        {
65          async: false
66        }
67      ]
68    ].filter(Boolean)
69  }
70}