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More helpful message when passing an element to createElement() #13131

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Merged
gaearon merged 10 commits into from
Aug 1, 2018
Merged

More helpful message when passing an element to createElement() #13131

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85a4ccb
[#13130] Add a more helpful message when passing an element to create…
DCtheTall Jun 30, 2018
24a071f
better conditional flow
DCtheTall Jun 30, 2018
4bf86b0
update after review
DCtheTall Jul 5, 2018
eafc93c
move last condition inside last else clause
DCtheTall Jul 17, 2018
453455d
Added test case
DCtheTall Jul 18, 2018
7d26762
compare 25132typeof to REACT_ELEMENT_TYPE
DCtheTall Jul 18, 2018
97bbb11
Merge branch 'master' into fix-issue-13130
DCtheTall Jul 18, 2018
537925f
runs prettier
DCtheTall Jul 18, 2018
55bf68a
remove unrelated changes
DCtheTall Jul 18, 2018
095832e
Tweak the message
gaearon Aug 1, 2018
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5 changes: 5 additions & 0 deletions packages/react/src/ReactElementValidator.js
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ import {
getIteratorFn,
REACT_FORWARD_REF_TYPE,
REACT_FRAGMENT_TYPE,
REACT_ELEMENT_TYPE,
} from 'shared/ReactSymbols';
import checkPropTypes from 'prop-types/checkPropTypes';
import warning from 'shared/warning';
Expand Down Expand Up @@ -286,6 +287,10 @@ export function createElementWithValidation(type, props, children) {
typeString = 'null';
} else if (Array.isArray(type)) {
typeString = 'array';
} else if (type !== undefined && type.$$typeof === REACT_ELEMENT_TYPE) {
typeString = `<${getComponentName(type.type) || 'Unknown'} />`;
info =
' Did you accidentally export a JSX literal instead of a component?';
} else {
typeString = typeof type;
}
Expand Down
20 changes: 20 additions & 0 deletions packages/react/src/__tests__/ReactElementValidator-test.internal.js
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Original file line number Diff line number Diff line change
Expand Up @@ -229,12 +229,17 @@ describe('ReactElementValidator', () => {
});

it('gives a helpful error when passing invalid types', () => {
function Foo() {}
expect(() => {
React.createElement(undefined);
React.createElement(null);
React.createElement(true);
React.createElement({x: 17});
React.createElement({});
React.createElement(React.createElement('div'));
React.createElement(React.createElement(Foo));
React.createElement(React.createElement(React.createContext().Consumer));
React.createElement({$$typeof: 'non-react-thing'});
}).toWarnDev(
[
'Warning: React.createElement: type is invalid -- expected a string ' +
Expand All @@ -256,6 +261,21 @@ describe('ReactElementValidator', () => {
'components) but got: object. You likely forgot to export your ' +
"component from the file it's defined in, or you might have mixed up " +
'default and named imports.',
'Warning: React.createElement: type is invalid -- expected a string ' +
'(for built-in components) or a class/function (for composite ' +
'components) but got: <div />. Did you accidentally export a JSX literal ' +
'instead of a component?',
'Warning: React.createElement: type is invalid -- expected a string ' +
'(for built-in components) or a class/function (for composite ' +
'components) but got: <Foo />. Did you accidentally export a JSX literal ' +
'instead of a component?',
'Warning: React.createElement: type is invalid -- expected a string ' +
'(for built-in components) or a class/function (for composite ' +
'components) but got: <Context.Consumer />. Did you accidentally ' +
'export a JSX literal instead of a component?',
'Warning: React.createElement: type is invalid -- expected a string ' +
'(for built-in components) or a class/function (for composite ' +
'components) but got: object.',
],
{withoutStack: true},
);
Expand Down