remix-project/.babelrc

{
  "plugins": ["fast-async",
              "check-es2015-constants",
              "transform-es2015-arrow-functions",
              "transform-es2015-block-scoped-functions",
              "transform-es2015-block-scoping",
              "transform-es2015-classes",
              "transform-es2015-computed-properties",
              "transform-es2015-destructuring",
              "transform-es2015-duplicate-keys",
              "transform-es2015-for-of",
              "transform-es2015-function-name",
              "transform-es2015-literals",
              "transform-es2015-object-super",
              "transform-es2015-parameters",
              "transform-es2015-shorthand-properties",
              "transform-es2015-spread",
              "transform-es2015-sticky-regex",
              "transform-es2015-unicode-regex",
              "transform-object-assign",
            ]
}