使用babel-jest的自定义转换器时发生意外的令牌导入

Question

When I run npm test ( jest --watch ), I get:

C:\sites\YDR\branches\trunk\development\app\static\js\_modules\marketplace\postbacks\Components\Form.js:44
import('Form').then(function (m) {
^^^^^^

SyntaxError: Unexpected token import

at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/ScriptTransformer.js:289:17)
at Object.<anonymous> (__tests__/postbacks-form.js:1:115)

Jest's part of package.json:

"jest": {
    "rootDir": "./../../",
    "modulePaths": [
      "<rootDir>tools/webpack/node_modules/",
      "<rootDir>development/app/static/css/_modules/",
      "<rootDir>development/app/static/js/_modules/"
    ],
    "transform": {
      "^.+\\.js$": "<rootDir>/tools/webpack/jest.transform.js"
    }
  }

jest.transform.js:

// Custom Jest transform implementation that wraps babel-jest and injects our
// babel presets, so we don't have to use .babelrc.
module.exports = require('babel-jest').createTransformer({
    presets: [
        require("babel-preset-react"),
        require("babel-preset-es2015")
    ],
    plugins: [
        require("babel-plugin-syntax-dynamic-import"),
    ]
});

I'm using following versions:

• node@8.1.3
• npm@5.3.0
• jest@20.0.4
• babel-core@6.25.0
• babel-jest@20.0.3
• babel-plugin-syntax-dynamic-import@6.18.0

I've also tried babel-plugin-dynamic-import-node@1.0.2, but then I have different error:

Plugin 0 specified in "base" provided an invalid property of "default"

Answer 1

Solved. It's a bug within babel-plugin-dynamic-import-node.

Can be work around by adding .default to require:

module.exports = require('babel-jest').createTransformer({
    presets: [
        require("babel-preset-react"),
        require("babel-preset-es2015")
    ],

    plugins: [
        require("babel-plugin-transform-es2015-modules-commonjs"),
        require("babel-plugin-dynamic-import-node").default,
    ]
});

Also, in order to be able to parse import() , babel-plugin-transform-es2015-modules-commonjs is needed.