babel – Kev's Development Toolbox

I ran into this error adding new Jest tests to my React project:

SyntaxError: CellComponent.test.js: Support for the experimental syntax 'jsx' isn't currently enabled (7:34):

and then this recommendation at the end:

Add @babel/preset-react (https://git.io/JfeDR) to the 'presets' section of your Babel config to enable transformation.

Doing an ‘npm i @babel/preset-react –save-dev’ gets us almost all the way there. Add a default babel.config.js with this config and you’re ready to go:

module.exports = {
    presets: [
      '@babel/preset-react',
      [ 
        '@babel/preset-env',
        {
          targets: {
            node: 'current',
          },
        },
      ],
    ],
  };

I pieced this together from multiple places, answers on this question got me in the right direction.

So far I’ve been using Jest with ES6 (see here), but to run Jest tests against React code using ES5, you might get errors when running your test and rendering the JSX.

Per the Jest docs, install the required Jest dependencies:

npm install --save-dev jest babel-jest babel-preset-es2015 babel-preset-react react-test-renderer

If you run ‘npm test’ at this point, any tests matching the *.test.* pattern will get executed, but you’ll probably also see an error ‘Unexpected token’ whenever a render() is called that contains JSX.

The quick fix in this SO question is to add a .babelrc containing this:

{ “presets”: [“es2015”, “react”] }

and then when Jest runs against your React components Babel will know how to transpile your JSX.

Tag: babel

Jest error parsing React jsx files “Support for the experimental syntax ‘jsx’ isn’t currently enabled”

Adding Jest to an ES5 project (‘Unexpected token’ errors on JSX)