Add dev hint about css object (generated by Babel) being stringified …

…by accident

.changeset/green-worms-grab.md

@@ -0,0 +1,6 @@
+---
+'babel-plugin-emotion': patch
+'@emotion/babel-preset-css-prop': patch
+---
+
+Add dev hint about css object (generated by Babel) being stringified by accident

packages/babel-plugin-emotion/__tests__/__snapshots__/index.js.snap

@@ -16,6 +16,8 @@ const SomeComponent = props => (
 
       ↓ ↓ ↓ ↓ ↓ ↓
 
+var _EMOTION_STRINGIFIED_CSS_ERROR__ = \\"You have tried to stringify object returned from \`css\` function. It isn't supposed to be used directly (e.g. as value of the \`className\` prop), but rather handed to emotion so it can handle it (e.g. as value of \`css\` prop).\\";
+
 /** @jsx jsx */
 import { jsx, css } from '@emotion/core';
 
@@ -25,7 +27,10 @@ var _ref = process.env.NODE_ENV === \\"production\\" ? {
 } : {
   name: \\"zszx19-SomeComponent\\",
   styles: \\"color:hotpink;;label:SomeComponent;\\",
-  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImNvcmUtd2l0aC1jc3MtaW1wb3J0LmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiJBQUtZIiwiZmlsZSI6ImNvcmUtd2l0aC1jc3MtaW1wb3J0LmpzIiwic291cmNlc0NvbnRlbnQiOlsiLyoqIEBqc3gganN4ICovXG5pbXBvcnQgeyBqc3gsIGNzcyB9IGZyb20gJ0BlbW90aW9uL2NvcmUnXG5cbmNvbnN0IFNvbWVDb21wb25lbnQgPSBwcm9wcyA9PiAoXG4gIDxkaXZcbiAgICBjc3M9e2Nzc2BcbiAgICAgIGNvbG9yOiBob3RwaW5rO1xuICAgIGB9XG4gICAgey4uLnByb3BzfVxuICAvPlxuKVxuIl19 */\\"
+  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImNvcmUtd2l0aC1jc3MtaW1wb3J0LmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiJBQUtZIiwiZmlsZSI6ImNvcmUtd2l0aC1jc3MtaW1wb3J0LmpzIiwic291cmNlc0NvbnRlbnQiOlsiLyoqIEBqc3gganN4ICovXG5pbXBvcnQgeyBqc3gsIGNzcyB9IGZyb20gJ0BlbW90aW9uL2NvcmUnXG5cbmNvbnN0IFNvbWVDb21wb25lbnQgPSBwcm9wcyA9PiAoXG4gIDxkaXZcbiAgICBjc3M9e2Nzc2BcbiAgICAgIGNvbG9yOiBob3RwaW5rO1xuICAgIGB9XG4gICAgey4uLnByb3BzfVxuICAvPlxuKVxuIl19 */\\",
+  toString: function () {
+    return _EMOTION_STRINGIFIED_CSS_ERROR__;
+  }
 };
 
 const SomeComponent = props => <div css={_ref} {...props} />;"
@@ -65,6 +70,7 @@ function Logo(props) {
 
       ↓ ↓ ↓ ↓ ↓ ↓
 
+var _EMOTION_STRINGIFIED_CSS_ERROR__ = \\"You have tried to stringify object returned from \`css\` function. It isn't supposed to be used directly (e.g. as value of the \`className\` prop), but rather handed to emotion so it can handle it (e.g. as value of \`css\` prop).\\";
 // @flow
 import * as React from 'react';
 import { jsx } from '@emotion/core';
@@ -75,7 +81,10 @@ var _ref = process.env.NODE_ENV === \\"production\\" ? {
 } : {
   name: \\"1f6ttp4-Logo\\",
   styles: \\"display:block;;label:Logo;\\",
-  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImZ1bmN0aW9uLWRlY2xhcmF0aW9uLmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiJBQU9NIiwiZmlsZSI6ImZ1bmN0aW9uLWRlY2xhcmF0aW9uLmpzIiwic291cmNlc0NvbnRlbnQiOlsiLy8gQGZsb3dcbmltcG9ydCAqIGFzIFJlYWN0IGZyb20gJ3JlYWN0J1xuaW1wb3J0IHsganN4IH0gZnJvbSAnQGVtb3Rpb24vY29yZSdcblxuZnVuY3Rpb24gTG9nbyhwcm9wcykge1xuICByZXR1cm4gKFxuICAgIDxhXG4gICAgICBjc3M9e3tcbiAgICAgICAgZGlzcGxheTogJ2Jsb2NrJ1xuICAgICAgfX1cbiAgICAvPlxuICApXG59XG4iXX0= */\\"
+  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImZ1bmN0aW9uLWRlY2xhcmF0aW9uLmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiJBQU9NIiwiZmlsZSI6ImZ1bmN0aW9uLWRlY2xhcmF0aW9uLmpzIiwic291cmNlc0NvbnRlbnQiOlsiLy8gQGZsb3dcbmltcG9ydCAqIGFzIFJlYWN0IGZyb20gJ3JlYWN0J1xuaW1wb3J0IHsganN4IH0gZnJvbSAnQGVtb3Rpb24vY29yZSdcblxuZnVuY3Rpb24gTG9nbyhwcm9wcykge1xuICByZXR1cm4gKFxuICAgIDxhXG4gICAgICBjc3M9e3tcbiAgICAgICAgZGlzcGxheTogJ2Jsb2NrJ1xuICAgICAgfX1cbiAgICAvPlxuICApXG59XG4iXX0= */\\",
+  toString: function () {
+    return _EMOTION_STRINGIFIED_CSS_ERROR__;
+  }
 };
 
 function Logo(props) {
@@ -109,6 +118,8 @@ const SomeComponent = props => (
 
       ↓ ↓ ↓ ↓ ↓ ↓
 
+var _EMOTION_STRINGIFIED_CSS_ERROR__ = \\"You have tried to stringify object returned from \`css\` function. It isn't supposed to be used directly (e.g. as value of the \`className\` prop), but rather handed to emotion so it can handle it (e.g. as value of \`css\` prop).\\";
+
 /** @jsx jsx */
 import { jsx } from '@emotion/core';
 
@@ -118,7 +129,10 @@ var _ref = process.env.NODE_ENV === \\"production\\" ? {
 } : {
   name: \\"zszx19-SomeComponent\\",
   styles: \\"color:hotpink;;label:SomeComponent;\\",
-  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImpzeC1ob2lzdC5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiQUFLSSIsImZpbGUiOiJqc3gtaG9pc3QuanMiLCJzb3VyY2VzQ29udGVudCI6WyIvKiogQGpzeCBqc3ggKi9cbmltcG9ydCB7IGpzeCB9IGZyb20gJ0BlbW90aW9uL2NvcmUnXG5cbmNvbnN0IFNvbWVDb21wb25lbnQgPSBwcm9wcyA9PiAoXG4gIDxkaXZcbiAgICBjc3M9e3tcbiAgICAgIGNvbG9yOiAnaG90cGluaydcbiAgICB9fVxuICAgIHsuLi5wcm9wc31cbiAgLz5cbilcbiJdfQ== */\\"
+  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImpzeC1ob2lzdC5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiQUFLSSIsImZpbGUiOiJqc3gtaG9pc3QuanMiLCJzb3VyY2VzQ29udGVudCI6WyIvKiogQGpzeCBqc3ggKi9cbmltcG9ydCB7IGpzeCB9IGZyb20gJ0BlbW90aW9uL2NvcmUnXG5cbmNvbnN0IFNvbWVDb21wb25lbnQgPSBwcm9wcyA9PiAoXG4gIDxkaXZcbiAgICBjc3M9e3tcbiAgICAgIGNvbG9yOiAnaG90cGluaydcbiAgICB9fVxuICAgIHsuLi5wcm9wc31cbiAgLz5cbilcbiJdfQ== */\\",
+  toString: function () {
+    return _EMOTION_STRINGIFIED_CSS_ERROR__;
+  }
 };
 
 const SomeComponent = props => <div css={_ref} {...props} />;"
@@ -142,6 +156,7 @@ function Logo(props) {
       ↓ ↓ ↓ ↓ ↓ ↓
 
 import _styled from \\"@emotion/styled-base\\";
+var _EMOTION_STRINGIFIED_CSS_ERROR__ = \\"You have tried to stringify object returned from \`css\` function. It isn't supposed to be used directly (e.g. as value of the \`className\` prop), but rather handed to emotion so it can handle it (e.g. as value of \`css\` prop).\\";
 // @flow
 import * as React from 'react';
 import { jsx } from '@emotion/core';
@@ -155,7 +170,10 @@ const MyObject = {
   } : {
     name: \\"1lrxbo5\\",
     styles: \\"color:hotpink;\\",
-    map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,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 */\\"
+    map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIm9iamVjdC1wcm9wZXJ0eS5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiQUFNYyIsImZpbGUiOiJvYmplY3QtcHJvcGVydHkuanMiLCJzb3VyY2VzQ29udGVudCI6WyIvLyBAZmxvd1xuaW1wb3J0ICogYXMgUmVhY3QgZnJvbSAncmVhY3QnXG5pbXBvcnQgeyBqc3ggfSBmcm9tICdAZW1vdGlvbi9jb3JlJ1xuaW1wb3J0IHN0eWxlZCBmcm9tICdAZW1vdGlvbi9zdHlsZWQnXG5cbmNvbnN0IE15T2JqZWN0ID0ge1xuICBNeVByb3BlcnR5OiBzdHlsZWQuZGl2KHsgY29sb3I6ICdob3RwaW5rJyB9KVxufVxuXG5mdW5jdGlvbiBMb2dvKHByb3BzKSB7XG4gIHJldHVybiA8TXlPYmplY3QuTXlQcm9wZXJ0eSAvPlxufVxuIl19 */\\",
+    toString: function () {
+      return _EMOTION_STRINGIFIED_CSS_ERROR__;
+    }
   })
 };
 
@@ -181,6 +199,8 @@ const SomeComponent = props => (
 
       ↓ ↓ ↓ ↓ ↓ ↓
 
+var _EMOTION_STRINGIFIED_CSS_ERROR__ = \\"You have tried to stringify object returned from \`css\` function. It isn't supposed to be used directly (e.g. as value of the \`className\` prop), but rather handed to emotion so it can handle it (e.g. as value of \`css\` prop).\\";
+
 /** @jsx jsx */
 import { jsx } from '@emotion/core';
 
@@ -190,7 +210,10 @@ var _ref = process.env.NODE_ENV === \\"production\\" ? {
 } : {
   name: \\"dwt66v-SomeComponent\\",
   styles: \\"color:hotpink;background-color:green;;label:SomeComponent;\\",
-  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0YXRpYy1vYmplY3Qtd2l0aC1jYW1lbC1jYXNlLmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiJBQUtJIiwiZmlsZSI6InN0YXRpYy1vYmplY3Qtd2l0aC1jYW1lbC1jYXNlLmpzIiwic291cmNlc0NvbnRlbnQiOlsiLyoqIEBqc3gganN4ICovXG5pbXBvcnQgeyBqc3ggfSBmcm9tICdAZW1vdGlvbi9jb3JlJ1xuXG5jb25zdCBTb21lQ29tcG9uZW50ID0gcHJvcHMgPT4gKFxuICA8ZGl2XG4gICAgY3NzPXt7XG4gICAgICBjb2xvcjogJ2hvdHBpbmsnLFxuICAgICAgYmFja2dyb3VuZENvbG9yOiAnZ3JlZW4nXG4gICAgfX1cbiAgICB7Li4ucHJvcHN9XG4gIC8+XG4pXG4iXX0= */\\"
+  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0YXRpYy1vYmplY3Qtd2l0aC1jYW1lbC1jYXNlLmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiJBQUtJIiwiZmlsZSI6InN0YXRpYy1vYmplY3Qtd2l0aC1jYW1lbC1jYXNlLmpzIiwic291cmNlc0NvbnRlbnQiOlsiLyoqIEBqc3gganN4ICovXG5pbXBvcnQgeyBqc3ggfSBmcm9tICdAZW1vdGlvbi9jb3JlJ1xuXG5jb25zdCBTb21lQ29tcG9uZW50ID0gcHJvcHMgPT4gKFxuICA8ZGl2XG4gICAgY3NzPXt7XG4gICAgICBjb2xvcjogJ2hvdHBpbmsnLFxuICAgICAgYmFja2dyb3VuZENvbG9yOiAnZ3JlZW4nXG4gICAgfX1cbiAgICB7Li4ucHJvcHN9XG4gIC8+XG4pXG4iXX0= */\\",
+  toString: function () {
+    return _EMOTION_STRINGIFIED_CSS_ERROR__;
+  }
 };
 
 const SomeComponent = props => <div css={_ref} {...props} />;"
@@ -218,6 +241,8 @@ const SomeComponent = props => {
 
       ↓ ↓ ↓ ↓ ↓ ↓
 
+var _EMOTION_STRINGIFIED_CSS_ERROR__ = \\"You have tried to stringify object returned from \`css\` function. It isn't supposed to be used directly (e.g. as value of the \`className\` prop), but rather handed to emotion so it can handle it (e.g. as value of \`css\` prop).\\";
+
 /** @jsx jsx */
 import { jsx } from '@emotion/core';
 
@@ -227,7 +252,10 @@ var _ref = process.env.NODE_ENV === \\"production\\" ? {
 } : {
   name: \\"1vvht02-SomeComponent\\",
   styles: \\"color:green;:hover{color:hotpink;};label:SomeComponent;\\",
-  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,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 */\\"
+  map: \\"/*# sourceMappingURL=data:application/json;charset=utf-8;base64,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 */\\",
+  toString: function () {
+    return _EMOTION_STRINGIFIED_CSS_ERROR__;
+  }
 };
 
 const SomeComponent = props => {