Typescript/nodejs：变量在某些位置隐式具有“any”类型

Question

我使用 typescript 和 nodejs 来初始化数据库数据，我想声明一个全局数组变量以在函数内部使用：

export { };
import {Address,CodePostal} from 'api/models';
const faker = require('faker')
const _ = require('lodash')
const quantity = 20
var codes

async function setup() {
  const adminUser1 = new User(ADMIN_USER_1);
  await adminUser1.save();

  await seedCodesPostal()
}

async function checkNewDB() {
  const adminUser1 = await User.findOne({ email: ADMIN_USER_1.email });
  if (!adminUser1) {
    console.log('- New DB detected ===> Initializing Dev Data...');
    await setup();
  } else {
    console.log('- Skip InitData');
  }
}

const seedCodesPostal = async () => {
  try {
    var codesPostal = []
    for (let i = 0; i < quantity; i++) {
      codesPostal.push(
        new CodePostal({
          codePostal: faker.address.zipCode("####")
        })
      )
    }
    codesPostal.forEach(async code => {
      await code.save()
    })
  } catch (err) {
    console.log(err);
  }
  codes = codesPostal ***// here is the error : variable codes has implicitly type 'any' in some locations where its type cannot be determined ***//
}

const seedAddresses = async (codes: any) => {
  try {
    const addresses = []
    for (let i = 0; i < quantity; i++) {
        addresses.push(
          new Address({
            street: faker.address.streetName(),
            city: faker.address.city(),
            number: faker.random.number(),
            codePostal: _.sample(codes),
            country: faker.address.country(),
            longitude: faker.address.longitude(),
            latitude: faker.address.latitude(),
          })
        )
    }

  } catch (error) {

  }
}

checkNewDB();

我想将codesPostal 的内容放入codes 变量内的函数seedCodesPostal 中，并将其作为参数传递到函数seedAddresses 中。

如何将代码变量定义为 CodesPostal correclty 数组？

Answer 1

当您创建一个类似类型的数组时，类型let arr = []被推断为any[]，因为 Typescript 不知道该数组中将包含什么。

因此，您只需将该数组键入为CodePostal实例数组：

var codesPostal: CodePostal[] = []

您还需要codes在try块内分配，否则如果触发codesPostal则永远无法设置。catch

通过这些编辑，您最终会得到简化的代码：

const quantity = 20

// Added type here
var codes: CodePostal[] = []

class CodePostal {
  async save() { }
}

const seedCodesPostal = async () => {
    try {
        // Added type here.
        var codesPostal: CodePostal[] = []

        for (let i = 0; i < quantity; i++) {
            codesPostal.push(
                new CodePostal()
            )
        }
        codesPostal.forEach(async code => {
            await code.save()
        })

        // Moved assignment inside try block
        codes = codesPostal

    } catch (err) {
        console.log(err);
    }
}

操场