How to connect login API in reactjs

I am creating login form for practice. I need to connect online API. I have no idea hot connect login API . I Just connect only fetch data API and not able to connect login API. I have design but not able to connect API .I am working in "react": "^16.12.0". using react hooks

enter code here

import React, { useState } from "react";
import { Wrapper } from "./vehiclesTableStyles";
import { PostData } from "./postData";

function VehiclesTable() {
const [username, setUsername] = useState("");
const [password, setPassword] = useState("");

const submitForm = e => {
e.preventDefault();

PostData(username, password).then(result => {
  console.log(result);
});
console.log("username", username);
console.log("password", password);
};
return (

<Wrapper>
  <div className="search_box">
    <form onSubmit={submitForm}>
      <input
        name="name"
        type="text"
        placeholder="username"
        onChange={e => setUsername(e.target.value)}
      />
      <input
        name="password"
        type="password"
        placeholder="search"
        onChange={e => setPassword(e.target.value)}
      />
      <input type="submit" value="login" />
    </form>
  </div>
</Wrapper>
);
}

export default VehiclesTable;



export function PostData(userData) {
let BaseUrl = "https://reqres.in//api/login";
console.log("userData", userData);
return new Promise((resolve, reject) => {
fetch(BaseUrl, {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    Accept: "application/json"
  }
  // body: JSON.stringify(userData)
})
  .then(response => response.json())
  .then(responseJson => {
    resolve(responseJson);
  })
  .catch(error => {
    reject(error);
  });
});
}

I also have the same problem. check the code below. You are making some mistake in code while calling api. You need to call in React life cycle hooks that is the best way.

enter code here

import React, { useState } from "react";
import { Wrapper } from "./vehiclesTableStyles";
import { PostData } from "./postData";

function VehiclesTable() {
const [username, setUsername] = useState("");
const [password, setPassword] = useState("");

const submitForm = e => {
e.preventDefault();

PostData(username, password).then(result => {
  console.log(result);
});
console.log("username", username);
console.log("password", password);
};
return (

<Wrapper>
  <div className="search_box">
    <form onSubmit={submitForm}>
      <input
        name="name"
        type="text"
        placeholder="username"
        onChange={e => setUsername(e.target.value)}
      />
      <input
        name="password"
        type="password"
        placeholder="search"
        onChange={e => setPassword(e.target.value)}
      />
      <input type="submit" value="login" />
    </form>
  </div>
</Wrapper>
);
}

export default VehiclesTable;



export function PostData(userData) {
let BaseUrl = "https://reqres.in//api/login";
console.log("userData", userData);
return new Promise((resolve, reject) => {
fetch(BaseUrl, {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    Accept: "application/json"
  }
  // body: JSON.stringify(userData)
})
  .then(response => response.json())
  .then(responseJson => {
    resolve(responseJson);
  })
  .catch(error => {
    reject(error);
  });
});