old_contents: import babel from 'rollup-plugin-babel';
  import { uglify } from 'rollup-plugin-uglify';
  import resolve from 'rollup-plugin-node-resolve';
  import commonjs from 'rollup-plugin-commonjs';
  
  export default [{
    input: 'src/main.js',
    output: {
      name: "_fetch",
      file: 'dist/index.umd.js',
      format: 'umd'
    },
    plugins: [
      babel({
        "include": "src/**",
        "plugins": [
          "istanbul",
        ]
      }),
      resolve(),
      commonjs()
    ]
  }, {
    input: 'src/main.js',
    output: {
      name: "_fetch",
      file: 'dist/index.umd.min.js',
      format: 'umd'
    },
    plugins: [
      babel({
        "include": "src/**",
      }),
      uglify(),
      resolve(),
      commonjs()
    ]
  }, {
    input: 'src/main.js',
    output: {
      file: 'dist/index.js',
      format: 'cjs'
    },
    plugins: [
      babel({
        "include": "src/**",
      }),
      uglify(),
      commonjs()
    ]
  }]
  
new_contents: import babel from 'rollup-plugin-babel';
  import { uglify } from 'rollup-plugin-uglify';
  import resolve from 'rollup-plugin-node-resolve';
  import commonjs from 'rollup-plugin-commonjs';
  
  export default [{
    input: 'src/main.js',
    output: {
      name: "_fetch",
      file: 'dist/index.umd.js',
      format: 'umd'
    },
    plugins: [
      babel({
        "include": "src/**",
        "plugins": [
          "istanbul",
        ]
      }),
      resolve(),
      commonjs()
    ]
  }, {
    input: 'src/main.js',
    output: {
      name: "_fetch",
      file: 'dist/index.umd.min.js',
      format: 'umd'
    },
    plugins: [
      babel({
        "include": "src/**",
      }),
      uglify(),
      resolve(),
      commonjs()
    ]
  }, {
    input: 'src/main.js',
    output: {
      file: 'dist/index.js',
      format: 'cjs'
    },
    external: [ 'whatwg-fetch' ],
    plugins: [
      babel({
        "include": "src/**",
      }),
      uglify(),
      commonjs()
    ]
  }]
  
subject: remove warn