Function onError

packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js:757–760

(x, errorInfo)

    const theError = new Error('Test');
    const loggedErrors = [];
    function onError(x, errorInfo) {
      loggedErrors.push(x);
      return 'Hash of (' + x.message + ')';
    }
    const expectedDigest = onError(theError);
    loggedErrors.length = 0;