babel.config.js

let plugins = [
  "@babel/plugin-transform-typescript",
  "transform-class-properties",
  [
    "@babel/transform-template-literals",
    {
      loose: true,
    },
  ],
  "@babel/transform-literals",
  "@babel/transform-function-name",
  "@babel/transform-arrow-functions",
  "@babel/transform-block-scoped-functions",
  "@babel/plugin-proposal-optional-chaining",
  [
    "@babel/plugin-transform-classes",
    {
      loose: true,
    },
  ],
  "@babel/transform-object-super",
  "@babel/transform-shorthand-properties",
  [
    "@babel/transform-computed-properties",
    {
      loose: true,
    },
  ],
  [
    "@babel/transform-for-of",
    {
      loose: true,
    },
  ],
  "@babel/transform-sticky-regex",
  "@babel/transform-unicode-regex",
  [
    "@babel/transform-spread",
    {
      loose: true,
    },
  ],
  "@babel/transform-parameters",
  [
    "@babel/transform-destructuring",
    {
      loose: true,
    },
  ],
  "@babel/transform-block-scoping",
  "@babel/plugin-transform-member-expression-literals",
  "@babel/transform-property-literals",
  "@babel/transform-async-to-generator",
  "@babel/transform-regenerator",
  [
    "@babel/transform-runtime",
    {
      regenerator: true,
    },
  ],
  "@babel/proposal-class-properties",
  "@babel/proposal-object-rest-spread",
];

let presets = [
  [
    "@babel/typescript",
    {
      loose: true,
      modules: false,
    },
  ],
];

if (process.env["NODE_ENV"] === "test") {
  presets = [
    ["@babel/preset-env", { targets: { node: "current" } }],
    "@babel/preset-typescript",
  ];
  plugins = [];
}

if (process.env["NODE_ENV"] === "es5") {
  presets = [
    [
      "@babel/typescript",
      {
        targets: {
          edge: "17",
          firefox: "60",
          chrome: "67",
          safari: "11.1",
          ie: "11",
        },
        useBuiltIns: false,
      },
    ],
  ];
  plugins.unshift("@babel/plugin-transform-modules-commonjs");
}

module.exports = {
  presets,
  plugins,
};