TSLINT 错误：属性“Component”在类型“typeof React”上不存在

Question

I downloaded the [react-native-redux-typescript-boilerplate]: https://reactnativeseed.com/ . The project runs smoothly in an android emulator. However, there are loads of tslint errors especially in the JSX syntax (ie, .tsx files). One major one is https://reactnativeseed.com/

I use webstrom as my code editor, and I crossed checked the version of typescript being used by webstrom and the project. There are the same.

These are the versions: 1. Typescript - 2.6.2 2. react-native - 0.59.6 3. react - 16.2.0 4. react-redux - 5.0.6 5. @types/react - "^16.8.14" 6. @types/react-native - "^0.47.7"

Is there anything else I need to check for?

I have also installed ["tslint-fix": "^0.1.3"]: https://www.npmjs.com/package/tslint-fix

ex: index.tsx

import * as React from "react";
import { Item, Input, Icon, Form, Toast } from "native-base";
import { Field, reduxForm } from "redux-form";
import Login from "../../stories/screens/Login";

const required = value => (value ? undefined : "Required");
const maxLength = max => value => (value && value.length > max ? `Must be ${max} characters or less` : undefined);
const maxLength15 = maxLength(15);
const minLength = min => value => (value && value.length < min ? `Must be ${min} characters or more` : undefined);
const minLength8 = minLength(8);
const email = value =>
    value && !/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i.test(value) ? "Invalid email address" : undefined;
const alphaNumeric = value => (value && /[^a-zA-Z0-9 ]/i.test(value) ? "Only alphanumeric characters" : undefined);

export interface Props {
    navigation: any;
    valid: boolean;
}
export interface State {}
class LoginForm extends React.Component<Props, State> {
    textInput: any;

    renderInput({ input, meta: { touched, error } }) {
        return (
            <Item error={error && touched}>
                <Icon active name={input.name === "email" ? "person" : "unlock"} />
                <Input
                    ref={c => (this.textInput = c)}
                    placeholder={input.name === "email" ? "Email" : "Password"}
                    secureTextEntry={input.name === "password" ? true : false}
                    {...input}
                />
            </Item>
        );
    }

    login() {
        if (this.props.valid) {
            this.props.navigation.navigate("Drawer");
        } else {
            Toast.show({
                text: "Enter Valid Username & password!",
                duration: 2000,
                position: "top",
                textStyle: { textAlign: "center" },
            });
        }
    }

    render() {
        const form = (
            <Form>
                <Field name="email" component={this.renderInput} validate={[email, required]} />
                <Field
                    name="password"
                    component={this.renderInput}
                    validate={[alphaNumeric, minLength8, maxLength15, required]}
                />
            </Form>
        );
        return <Login loginForm={form} onLogin={() => this.login()} />;
    }
}
const LoginContainer = reduxForm({
    form: "login",
})(LoginForm);
export default LoginContainer;

in the above file in the render() a lot of errors are shown. some of it are: 1. Property 'Component' does not exist on type 'typeof React'. 2. JSX element type 'Item' is not a constructor function for JSX elements. Property 'render' is missing in type 'Item'. and many more similar one.

Answer 1

I finally resolved the issue. @types/react was using typescript version 2.8.1 while my project was using typescript version 2.6.2. So, I upgraded my project's typescript version to 2.8.1 and the errors were gone.

Answer 2

You forgot to import React

import React, { Component } from 'react';

Replace class LoginForm extends React.Component<Props, State> with class LoginForm extends Component<Props, State>