Question

我在以下TypeScript代码中收到了Eslint警告：

“ function.eslint（@ typescript-eslint / explicit-function-return-type）上缺少返回类型。”警告是指map函数中的lambda。

private headerSelectionChanged(event): void {
    const { checked } = event.syntheticEvent.target;
    const newGridData = this.props.gridData.map(item => Object.assign(item, { selected: checked }));
    this.updateGridData(newGridData);
}

怎么了？我该如何解决？

Answer 1

显示警告，因为您的映射函数未指定返回类型。您必须这样指定返回类型：

const newGridData = this.props.gridData.map((item): any => Object.assign(item, { selected: checked }));

请记住，Object.assign会修改目标，而不是复制目标。如果您不希望修改this.props.gridData，则应交换item和{ selected: checked }

const newGridData = this.props.gridData.map((item): any => Object.assign({ selected: checked }, item));

或使用较新的object spread operator（如果有）：

const newGridData = this.props.gridData.map((item): any => ({ ...item, selected: checked }));

Answer 2

尝试添加类似的类型：

private headerSelectionChanged(event: any): void {
const { checked } = event.syntheticEvent.target;
const newGridData = this.props.gridData.map((item: any) => Object.assign(item, { selected: checked }));
this.updateGridData(newGridData);

}

array.map中缺少返回类型

2 个答案: