javascript - Flow - 如何在另一种类型中使用声明的类型？

Question

import type {crusherDowntimeRecord} from "./downtime/types";

type Props = {
  data: Array<crusherDowntimeRecord>,
};
type State = {
  rows: Props.data,
};

在 Props.data 上抛出:

Error:(30, 15) Cannot get Props.data because property data is missing in Props [1].

怎么了？

Answer 1

您不能通过Props 访问data，因为它是type，而不是javascript object。对于解决方案，使用 flow $PropertyType:

import type {CrusherDowntimeRecord} from "./downtime/types";

type Props = {
  data: Array<CrusherDowntimeRecord>,
};

type State = {
  rows: $PropertyType<Props, 'data'>,
};

Flow - Property type

FlowTry - Example