我刚刚开始使用Flow，并且在使用它来扫描React Native项目后我遇到了一堆错误：
Error --------------------------- node_modules
Missing type annotation for `U`.
v--------------------------
353| return range.map(function(value) {
354| if (typeof value !== 'string') {
355| return value;
356| }
357| if (/deg$/.test(value)) {
358| const degrees = parseFloat(value) || 0;
359| const radians = degrees * Math.PI / 180.0;
360| return radians;
361| } else {
362| // Assume radians
363| return parseFloat(value) || 0;
364| }
365| });
-^
Error ------------------------------------ node_modules/react-native/Librarie
Property `update` is missing in `AnimatedNode` [1].
node_modules/react-native/Libraries/Animated/src/nodes/AnimatedValue.js:54
54| if (typeof node.update === 'function') {
^^^^^^^^^^^
References:
node_modules/react-native/Libraries/Animated/src/nodes/AnimatedWithChildre
70| __getChildren(): Array<AnimatedNode> {
^^^^^^^^^^^^ [1]
Error -------------------------------------------- node_modules/react-native/
Cannot assign `!this.props.disabled` to `props.enabled` because property `ena
node_modules/react-native/Libraries/Components/Switch/Switch.js:105:7
105| props.enabled = !this.props.disabled;
^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/Components/Switch/Switch.js:101:19
101| const props = {...this.props};
^^^^^^^^^^^^^^^ [1]
Error -------------------------------------------- node_modules/react-native/
Cannot assign `this.props.value` to `props.on` because property `on` is missi
node_modules/react-native/Libraries/Components/Switch/Switch.js:106:7
106| props.on = this.props.value;
^^^^^^^^
References:
node_modules/react-native/Libraries/Components/Switch/Switch.js:101:19
101| const props = {...this.props};
^^^^^^^^^^^^^^^ [1]
Error -------------------------------------------- node_modules/react-native/
Cannot assign `this.props.value ? this.props.onTintColor : this.props.tintCol
property `trackTintColor` is missing in object literal [1].
node_modules/react-native/Libraries/Components/Switch/Switch.js:108:7
108| props.trackTintColor = this.props.value ? this.props.onTintColo
^^^^^^^^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/Components/Switch/Switch.js:101:19
101| const props = {...this.props};
^^^^^^^^^^^^^^^ [1]
Error ------------------------ node_modules/react-native/Libraries/Experiment
Property `setNativeProps` is missing in `React.Element` [1].
node_modules/react-native/Libraries/Experimental/SwipeableRow/SwipeableLis
145| if (this._listViewRef && typeof this._listViewRef.setNativeProps
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/Experimental/SwipeableRow/SwipeableLis
58| _listViewRef: ?React.Element<any> = null;
^^^^^^^^^^^^^^^^^^ [1]
Error ------------------------ node_modules/react-native/Libraries/Experiment
Property `getScrollResponder` is missing in `React.Element` [1].
node_modules/react-native/Libraries/Experimental/SwipeableRow/SwipeableLis
154| if (this._listViewRef && typeof this._listViewRef.getScrollRespon
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/Experimental/SwipeableRow/SwipeableLis
58| _listViewRef: ?React.Element<any> = null;
^^^^^^^^^^^^^^^^^^ [1]
Error ----------------------------------------------- node_modules/react-nati
Cannot assign array literal to `scrollProps.style` because property `style` i
node_modules/react-native/Libraries/Lists/VirtualizedList.js:908:7
908| scrollProps.style = [inversionStyle, this.props.style];
^^^^^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/Lists/VirtualizedList.js:893:25
v
893| const scrollProps = {
894| ...this.props,
895| onContentSizeChange: this._onContentSizeChange,
896| onLayout: this._onLayout,
897| onScroll: this._onScroll,
898| onScrollBeginDrag: this._onScrollBeginDrag,
899| onScrollEndDrag: this._onScrollEndDrag,
900| onMomentumScrollEnd: this._onMomentumScrollEnd,
901| scrollEventThrottle: this.props.scrollEventThrottle, // TODO: A
902| invertStickyHeaders: this.props.invertStickyHeaders !== undefin
903| ? this.props.invertStickyHeaders
904| : this.props.inverted,
905| stickyHeaderIndices,
906| };
^ [1]
Error --------------------------------------------- node_modules/react-native
Property `inLayout` is missing in object type [1].
node_modules/react-native/Libraries/Lists/VirtualizedList.js:1125:11
1125| if (frame.inLayout) {
^^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/Lists/VirtualizedList.js:1474:6
1474| ): {length: number, offset: number} => {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ [1]
Error --------------------------------------------- node_modules/react-native
Property `debug` is missing in object type [1].
node_modules/react-native/Libraries/Lists/VirtualizedList.js:1649:25
1649| getItemLayout && !parentProps.debug && !fillRateHelper.enabled
^^^^^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/Lists/VirtualizedList.js:1567:18
v
1567| parentProps: {
1568| getItemLayout?: ?Function,
1569| renderItem: renderItemType,
1570| },
^ [1]
Error ----------------------------------------------- node_modules/react-nati
Property `disableYellowBox` is missing in object type [1].
node_modules/react-native/Libraries/ReactNative/YellowBox.js:108:7
108| if (console.disableYellowBox) {
^^^^^^^^^^^^^^^^^^^^^^^^
References:
C:\cygwin64\tmp\flow\flowlib_1ec88eef\core.js:806:22
v-
806| declare var console: {
807| assert(condition: mixed, ...data: Array<any>): void;
808| clear(): void;
809| count(label: string): void;
810| debug(...data: Array<any>): void;
811| dir(...data: Array<any>): void;
812| dirxml(...data: Array<any>): void;
813| error(...data: Array<any>): void;
814| _exception(...data: Array<any>): void;
815| group(...data: Array<any>): void;
816| groupCollapsed(...data: Array<any>): void;
817| groupEnd(): void;
818| info(...data: Array<any>): void;
819| log(...data: Array<any>): void;
820| profile(name?: string): void;
821| profileEnd(name?: string): void;
822| table(tabularData: { [key: string]: any } | Array<{ [key: string]:
823| time(label: string): void;
824| timeEnd(label: string): void;
825| timeStamp(label?: string): void;
826| trace(...data: Array<any>): void;
827| warn(...data: Array<any>): void;
828| };
^ [1]
Error ---------------------------------------------- node_modules/react-nativ
Property `ignoredYellowBox` is missing in object type [1].
node_modules/react-native/Libraries/ReactNative/YellowBox.js:181:19
181| Array.isArray(console.ignoredYellowBox) &&
^^^^^^^^^^^^^^^^^^^^^^^^
References:
C:\cygwin64\tmp\flow\flowlib_1ec88eef\core.js:806:22
v-
806| declare var console: {
807| assert(condition: mixed, ...data: Array<any>): void;
808| clear(): void;
809| count(label: string): void;
810| debug(...data: Array<any>): void;
811| dir(...data: Array<any>): void;
812| dirxml(...data: Array<any>): void;
813| error(...data: Array<any>): void;
814| _exception(...data: Array<any>): void;
815| group(...data: Array<any>): void;
816| groupCollapsed(...data: Array<any>): void;
817| groupEnd(): void;
818| info(...data: Array<any>): void;
819| log(...data: Array<any>): void;
820| profile(name?: string): void;
821| profileEnd(name?: string): void;
822| table(tabularData: { [key: string]: any } | Array<{ [key: string]:
823| time(label: string): void;
824| timeEnd(label: string): void;
825| timeStamp(label?: string): void;
826| trace(...data: Array<any>): void;
827| warn(...data: Array<any>): void;
828| };
^ [1]
Error ----------------------------------------------- node_modules/react-nati
Property `disableYellowBox` is missing in object type [1].
node_modules/react-native/Libraries/ReactNative/YellowBox.js:382:9
382| if (console.disableYellowBox || this.state.warningMap.size === 0)
^^^^^^^^^^^^^^^^^^^^^^^^
References:
C:\cygwin64\tmp\flow\flowlib_1ec88eef\core.js:806:22
v-
806| declare var console: {
807| assert(condition: mixed, ...data: Array<any>): void;
808| clear(): void;
809| count(label: string): void;
810| debug(...data: Array<any>): void;
811| dir(...data: Array<any>): void;
812| dirxml(...data: Array<any>): void;
813| error(...data: Array<any>): void;
814| _exception(...data: Array<any>): void;
815| group(...data: Array<any>): void;
816| groupCollapsed(...data: Array<any>): void;
817| groupEnd(): void;
818| info(...data: Array<any>): void;
819| log(...data: Array<any>): void;
820| profile(name?: string): void;
821| profileEnd(name?: string): void;
822| table(tabularData: { [key: string]: any } | Array<{ [key: string]:
823| time(label: string): void;
824| timeEnd(label: string): void;
825| timeStamp(label?: string): void;
826| trace(...data: Array<any>): void;
827| warn(...data: Array<any>): void;
828| };
^ [1]
Error ---------------------------------------- node_modules/react-native/Libr
Property `prototype` is missing in `React.StatelessFunctionalComponent` [1].
node_modules/react-native/Libraries/ReactNative/renderApplication.js:41:5
41| RootComponent.prototype != null &&
^^^^^^^^^^^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/ReactNative/renderApplication.js:24:18
24| RootComponent: React.ComponentType<Props>,
^^^^^^^^^^^^^^^^^^^^^^^^^^ [1]
Error --------------------------------- node_modules/react-native/Libraries/R
Property `__propTypesSecretDontUseThesePlease` is missing in `React.Stateless
node_modules/react-native/Libraries/ReactNative/requireNativeComponent.js:
122| typeof componentInterface.__propTypesSecretDontUseThesePlease
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
References:
node_modules/react-native/Libraries/ReactNative/requireNativeComponent.js:
50| componentInterface?: ?ComponentInterface,
^^^^^^^^^^^^^^^^^^ [1]
Error -----------------------------------------------------------------------
My Flow版本为0.72.0，我的React Native版本为0.55.3。我能做错什么？
答案 0 :(得分：1)
Array.map中的 lib.es5.d.ts方法被注释为
map<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[];
存在一种通用类型U，用于表示数组元素的类型，此类型在映射后由此方法返回。
当Flow在抱怨Missing type annotation for `U`.时，很可能是因为Flow由于某种原因无法自动推断出该类型，因此您应该明确声明它：
function XXX(YYYY): (some_type | number)[] { // <-- you should explicitly declare return type here
...
return range.map(function(value: some_type|string) { // <--- probably, more explicit typehint here as well
if (typeof value !== 'string') {
return value; // <-- return value is a 'some_type' here
}
if (/deg$/.test(value)) {
const degrees = parseFloat(value) || 0;
const radians = degrees * Math.PI / 180.0;
return radians; // <-- return value is 'number' here
} else {
// Assume radians
return parseFloat(value) || 0; // <-- return value is 'number' here
}
});
}
其余错误大部分来自React类型定义，因为它对DOM元素/节点（例如readonly等）和ReactNative类型提示的现有对象属性的覆盖不完整，因为它们通常是不完整的。