sass-vars-loader: Variables undefined when use sass-loader.options.data attribute

Hello! I use sass-vars-loader with Vue Cli 3 and I try to move common scss-files to app config:

const path = require('path');

module.exports = {
  chainWebpack: (config) => {
    const moduleTypes = ['vue-modules', 'vue', 'normal-modules', 'normal'];
    moduleTypes.forEach(moduleType =>
      config.module
        .rule('scss')
        .oneOf(moduleType)
        .use('@epegzz/sass-vars-loader')
        .loader('@epegzz/sass-vars-loader')
        .options({
          syntax: 'scss',
          files: [
            path.resolve(__dirname, 'src/assets/styles/contracts/variables.json'),
            path.resolve(__dirname, 'src/assets/styles/contracts/icons.json')
          ],
        })
    )
  },

  css: {
    loaderOptions: {
      sass: {
        data: `
          @import '~@/assets/styles/vars';
          @import '~@/assets/styles/util';
          @import '~@/assets/styles/func';
          @import '~@/assets/styles/mixins';
          @import '~@/assets/styles/colors';
        `,
      },
    },
  },
}

But on app loaded I have got an error: “Undefined variable: $palette”. It works properly, when I importing common scss-files directly, but I want to import it all in one place.

Can you help me?