preventDefault not working when form submit react js

No need to pass the state to this.formSubmitHandler because you can access it inside the function itself.

import React from "react";

export default class App extends React.Component {
  constructor(props) {
    super(props);

    this.state = { username: "", password: "", logtype: "" };

    this.usernameHandler = this.usernameHandler.bind(this);
    this.passwordHandler = this.passwordHandler.bind(this);
    this.typeHandler = this.typeHandler.bind(this);
    this.formSubmitHandler = this.formSubmitHandler.bind(this);
  }

  usernameHandler() {
    // your code
  }

  passwordHandler() {
    // your code
  }

  typeHandler() {
    // your code
  }

  formSubmitHandler(e) {
    e.preventDefault();
    console.log(this.state);
  }

  render() {
    return (
      <div>
        <form onSubmit={this.formSubmitHandler}>
          <input
            type="text"
            placeholder="Username"
            value={this.state.username}
            onChange={this.usernameHandler}
          />
          <input
            type="password"
            placeholder="Password"
            value={this.state.password}
            onChange={this.passwordHandler}
          />
          <select value={this.state.logtype} onChange={this.typeHandler}>
            <option value="Primary"> Primary</option>
            <option value="Secondary"> Secondary</option>
          </select>
          <button>Submit</button>
        </form>
      </div>
    );
  }
}