Dynamic interpolations that contain "this" fail under some circumstances

[gnandretta]

The interpolation below works in next v5 but since v6 (which uses babel 7) it throws a TypeError: Cannot read property 'props' of undefined.

export default class Index extends React.Component {
  static getInitialProps() {
    return { color: 'aquamarine' };
  }

  render() {
    return (
      <div>
        {[1,2].map(idx => <div key={idx}>{this.props.color}</div>)}
        <style jsx>{`
          div {
            background: ${this.props.color};
          }
        `}</style>
      </div>
    );
  }
}

Sample apps

• Working application using next 5. Here's its source code.
• Application showing the issue using next 7 canary. Logs with the error can be seen here and source code is the same as the app above.

Details

Below is the babel output of the class for both applications. Note how in next 5 both this.props.color expressions, that is, the style interpolation and the div children, are compiled to _this2.props.color. However, in next 7, the style interpolation is compiled to this.props.color while the div children is compiled to _this.props.color.

Compiled class in next 5 app

_createClass(Index, [{
  key: 'render',
  value: function render() {
    var _this2 = this;

    return __WEBPACK_IMPORTED_MODULE_1_react___default.a.createElement(
      'div',
      {
        className: __WEBPACK_IMPORTED_MODULE_0_styled_jsx_style___default.a.dynamic([['1028791522', [_this2.props.color]]]),
        __source: {
          fileName: _jsxFileName,
          lineNumber: 8
        }
      },
      [1, 2].map(function (idx) {
        return __WEBPACK_IMPORTED_MODULE_1_react___default.a.createElement(
          'div',
          { key: idx, className: __WEBPACK_IMPORTED_MODULE_0_styled_jsx_style___default.a.dynamic([['1028791522', [_this2.props.color]]]),
            __source: {
              fileName: _jsxFileName,
              lineNumber: 9
            }
          },
          _this2.props.color
        );
      }),
      __WEBPACK_IMPORTED_MODULE_1_react___default.a.createElement(__WEBPACK_IMPORTED_MODULE_0_styled_jsx_style___default.a, {
        styleId: '1028791522',
        css: 'div.__jsx-style-dynamic-selector{background:' + _this2.props.color + ';}\n/*# sourceMappingURL=data:application/json;charset=utf-8;base64,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 */\n/*@ sourceURL=pages/index.js */',
        dynamic: [_this2.props.color]
      })
    );
  }
}, {
  key: '__reactstandin__regenerateByEval',
  value: function __reactstandin__regenerateByEval(key, code) {
    this[key] = eval(code);
  }
}], [{
  key: 'getInitialProps',
  value: function getInitialProps() {
    return { color: 'aquamarine' };
  }
}]);

Compiled class in next 7 app

_createClass(Index, [{
  key: "render",
  value: function render() {
    var _this = this;

    return react__WEBPACK_IMPORTED_MODULE_1___default.a.createElement("div", {
      __source: {
        fileName: _jsxFileName,
        lineNumber: 8
      },
      className: styled_jsx_style__WEBPACK_IMPORTED_MODULE_0___default.a.dynamic([["1028791522", [this.props.color]]])
    }, [1, 2].map(function (idx) {
      return react__WEBPACK_IMPORTED_MODULE_1___default.a.createElement("div", {
        key: idx,
        __source: {
          fileName: _jsxFileName,
          lineNumber: 9
        },
        className: styled_jsx_style__WEBPACK_IMPORTED_MODULE_0___default.a.dynamic([["1028791522", [this.props.color]]])
      }, _this.props.color);
    }), react__WEBPACK_IMPORTED_MODULE_1___default.a.createElement(styled_jsx_style__WEBPACK_IMPORTED_MODULE_0___default.a, {
      styleId: "1028791522",
      css: "div.__jsx-style-dynamic-selector{background:".concat(this.props.color, ";}\n/*# sourceMappingURL=data:application/json;charset=utf-8;base64,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 */\n/*@ sourceURL=pages/index.js */"),
      dynamic: [this.props.color]
    }));
  }
}], [{
  key: "getInitialProps",
  value: function getInitialProps() {
    return {
      color: 'aquamarine'
    };
  }
}])

[giuseppeg]

thanks Gabriel, that's indeed a bug and has to do with AST nodes reusing. We probably don't clone some node. We had a similar issue before #470