| 1 | /** @flow */ |
| 2 | |
| 3 | import * as React from 'react'; |
| 4 | import {Fragment, useEffect, useRef, useState} from 'react'; |
| 5 | |
| 6 | // $FlowFixMe[missing-local-annot] |
| 7 | function WarnDuringRender({children = null}) { |
| 8 | console.warn('This warning fires during every render'); |
| 9 | return children; |
| 10 | } |
| 11 | |
| 12 | // $FlowFixMe[missing-local-annot] |
| 13 | function WarnOnMount({children = null}) { |
| 14 | useEffect(() => { |
| 15 | console.warn('This warning fires on initial mount only'); |
| 16 | }, []); |
| 17 | return children; |
| 18 | } |
| 19 | |
| 20 | // $FlowFixMe[missing-local-annot] |
| 21 | function WarnOnUpdate({children = null}) { |
| 22 | const didMountRef = useRef(false); |
| 23 | useEffect(() => { |
| 24 | if (didMountRef.current) { |
| 25 | console.warn('This warning fires on every update'); |
| 26 | } else { |
| 27 | didMountRef.current = true; |
| 28 | } |
| 29 | }); |
| 30 | return children; |
| 31 | } |
| 32 | |
| 33 | // $FlowFixMe[missing-local-annot] |
| 34 | function WarnOnUnmount({children = null}) { |
| 35 | useEffect(() => { |
| 36 | return () => { |
| 37 | console.warn('This warning fires on unmount'); |
| 38 | }; |
| 39 | }, []); |
| 40 | return children; |
| 41 | } |
| 42 | |
| 43 | // $FlowFixMe[missing-local-annot] |
| 44 | function ErrorDuringRender({children = null}) { |
| 45 | console.error('This error fires during every render'); |
| 46 | return children; |
| 47 | } |
| 48 | |
| 49 | // $FlowFixMe[missing-local-annot] |
| 50 | function ErrorOnMount({children = null}) { |
| 51 | useEffect(() => { |
| 52 | console.error('This error fires on initial mount only'); |
| 53 | }, []); |
| 54 | return children; |
| 55 | } |
| 56 | |
| 57 | // $FlowFixMe[missing-local-annot] |
| 58 | function ErrorOnUpdate({children = null}) { |
| 59 | const didMountRef = useRef(false); |
| 60 | useEffect(() => { |
| 61 | if (didMountRef.current) { |
| 62 | console.error('This error fires on every update'); |
| 63 | } else { |
| 64 | didMountRef.current = true; |
| 65 | } |
| 66 | }); |
| 67 | return children; |
| 68 | } |
| 69 | |
| 70 | // $FlowFixMe[missing-local-annot] |
| 71 | function ErrorOnUnmount({children = null}) { |
| 72 | useEffect(() => { |
| 73 | return () => { |
| 74 | console.error('This error fires on unmount'); |
| 75 | }; |
| 76 | }, []); |
| 77 | return children; |
| 78 | } |
| 79 | |
| 80 | // $FlowFixMe[missing-local-annot] |
| 81 | function ErrorAndWarningDuringRender({children = null}) { |
| 82 | console.warn('This warning fires during every render'); |
| 83 | console.error('This error fires during every render'); |
| 84 | return children; |
| 85 | } |
| 86 | |
| 87 | // $FlowFixMe[missing-local-annot] |
| 88 | function ErrorAndWarningOnMount({children = null}) { |
| 89 | useEffect(() => { |
| 90 | console.warn('This warning fires on initial mount only'); |
| 91 | console.error('This error fires on initial mount only'); |
| 92 | }, []); |
| 93 | return children; |
| 94 | } |
| 95 | |
| 96 | // $FlowFixMe[missing-local-annot] |
| 97 | function ErrorAndWarningOnUpdate({children = null}) { |
| 98 | const didMountRef = useRef(false); |
| 99 | useEffect(() => { |
| 100 | if (didMountRef.current) { |
| 101 | console.warn('This warning fires on every update'); |
| 102 | console.error('This error fires on every update'); |
| 103 | } else { |
| 104 | didMountRef.current = true; |
| 105 | } |
| 106 | }); |
| 107 | return children; |
| 108 | } |
| 109 | |
| 110 | // $FlowFixMe[missing-local-annot] |
| 111 | function ErrorAndWarningOnUnmount({children = null}) { |
| 112 | useEffect(() => { |
| 113 | return () => { |
| 114 | console.warn('This warning fires on unmount'); |
| 115 | console.error('This error fires on unmount'); |
| 116 | }; |
| 117 | }, []); |
| 118 | return children; |
| 119 | } |
| 120 | |
| 121 | // $FlowFixMe[missing-local-annot] |
| 122 | function ReallyLongErrorMessageThatWillCauseTextToBeTruncated({ |
| 123 | children = null, |
| 124 | }) { |
| 125 | console.error( |
| 126 | 'This error is a really long error message that should cause the text to be truncated in DevTools', |
| 127 | ); |
| 128 | return children; |
| 129 | } |
| 130 | |
| 131 | // $FlowFixMe[missing-local-annot] |
| 132 | function ErrorWithMultipleArgs({children = null}) { |
| 133 | console.error('This error', 'passes console', 4, 'arguments'); |
| 134 | return children; |
| 135 | } |
| 136 | |
| 137 | // $FlowFixMe[missing-local-annot] |
| 138 | function ErrorWithStringSubstitutions({children = null}) { |
| 139 | console.error('This error uses "%s" substitutions', 'string'); |
| 140 | return children; |
| 141 | } |
| 142 | |
| 143 | // $FlowFixMe[missing-local-annot] |
| 144 | function ReactErrorOnHostComponent({children = null}) { |
| 145 | return <div data-camelCasedAttribute="should-lower-case">{children}</div>; |
| 146 | } |
| 147 | |
| 148 | // $FlowFixMe[missing-local-annot] |
| 149 | function DuplicateWarningsAndErrors({children = null}) { |
| 150 | console.warn('this warning is logged twice per render'); |
| 151 | console.warn('this warning is logged twice per render'); |
| 152 | console.error('this error is logged twice per render'); |
| 153 | console.error('this error is logged twice per render'); |
| 154 | return <div data-camelCasedAttribute="should-lower-case">{children}</div>; |
| 155 | } |
| 156 | |
| 157 | // $FlowFixMe[missing-local-annot] |
| 158 | function MultipleWarningsAndErrors({children = null}) { |
| 159 | console.warn('this is the first warning logged'); |
| 160 | console.warn('this is the second warning logged'); |
| 161 | console.error('this is the first error logged'); |
| 162 | console.error('this is the second error logged'); |
| 163 | return <div data-camelCasedAttribute="should-lower-case">{children}</div>; |
| 164 | } |
| 165 | |
| 166 | // $FlowFixMe[missing-local-annot] |
| 167 | function ComponentWithMissingKey({children}) { |
| 168 | return [<div />]; |
| 169 | } |
| 170 | |
| 171 | function ComponentWithSymbolWarning() { |
| 172 | console.warn('this is a symbol', Symbol('foo')); |
| 173 | console.error('this is a symbol', Symbol.for('bar')); |
| 174 | return null; |
| 175 | } |
| 176 | |
| 177 | export default function ErrorsAndWarnings(): React.Node { |
| 178 | const [count, setCount] = useState(0); |
| 179 | const handleClick = () => setCount(count + 1); |
| 180 | return ( |
| 181 | <Fragment> |
| 182 | <h1>Inline warnings</h1> |
| 183 | <button onClick={handleClick}>Update {count > 0 ? count : ''}</button> |
| 184 | <ComponentWithMissingKey /> |
| 185 | <WarnDuringRender /> |
| 186 | <WarnOnMount /> |
| 187 | <WarnOnUpdate /> |
| 188 | {count === 0 ? <WarnOnUnmount /> : null} |
| 189 | {count === 0 ? <WarnOnMount /> : null} |
| 190 | <ErrorDuringRender /> |
| 191 | <ErrorOnMount /> |
| 192 | <ErrorOnUpdate /> |
| 193 | {count === 0 ? <ErrorOnUnmount /> : null} |
| 194 | <ErrorAndWarningDuringRender /> |
| 195 | <ErrorAndWarningOnMount /> |
| 196 | <ErrorAndWarningOnUpdate /> |
| 197 | {count === 0 ? <ErrorAndWarningOnUnmount /> : null} |
| 198 | <ErrorWithMultipleArgs /> |
| 199 | <ErrorWithStringSubstitutions /> |
| 200 | <ReactErrorOnHostComponent /> |
| 201 | <ReallyLongErrorMessageThatWillCauseTextToBeTruncated /> |
| 202 | <DuplicateWarningsAndErrors /> |
| 203 | <MultipleWarningsAndErrors /> |
| 204 | <ComponentWithSymbolWarning /> |
| 205 | </Fragment> |
| 206 | ); |
| 207 | } |