Reactjs - How can i save dark light mode in local storage with typescript?

PashaMammadov
July 26, 2023
119 views
1 vote
2 Answers

import { createContext, useState } from "react";

export interface TypeContext {
  darkMode: true | false;
  setDarkMode: React.Dispatch<React.SetStateAction<boolean>>;
  toggleMode: () => void;
}

export interface TypeChildrenProps {
  children: JSX.Element;
}

export const GlobalThemeContext = createContext<TypeContext>({
  darkMode: false,
  setDarkMode: () => {},
  toggleMode: () => {},
});

export const ThemeContextProvider = ({ children }: TypeChildrenProps) => {
  const [darkMode, setDarkMode] = useState(false);

  // useState(localStorage.getItem('Mode') ? JSON.parse(localStorage.getItem('Mode') : false))
  // Argument of type 'string | null' is not assignable to parameter of type 'string'.
  // Type 'null' is not assignable to type 'string'

  const toggleMode = () => {
    setDarkMode(!darkMode);
  };

  return (
    <GlobalThemeContext.Provider value={{ darkMode, setDarkMode, toggleMode }}>
      {children}
    </GlobalThemeContext.Provider>
  );
};

Hello. I type in dark light mode using context with typescript, everything works fine. I have applied it to other pages, when you click the button, the mode changes. The only problem is that it disappears when you refresh it. How can I make it stay in local storage?

I added img code :

Answers

Your answer is nearly right

Here, are the changes you can do get it through

import { createContext, useState } from "react";

export interface TypeContext {
  darkMode: true | false;
  setDarkMode: React.Dispatch<React.SetStateAction<boolean>>;
  toggleMode: () => void;
}

export interface TypeChildrenProps {
  children: JSX.Element;
}

export const GlobalThemeContext = createContext<TypeContext>({
  darkMode: false,
  setDarkMode: () => {},
  toggleMode: () => {},
});

export const ThemeContextProvider = ({ children }: TypeChildrenProps) => {
  const [darkMode, setDarkMode] = useState<boolean | null>(localStorage.getItem('Mode') ? JSON.parse(localStorage.getItem('Mode') : false))
  // Argument of type 'string | null' is not assignable to parameter of type 'string'.
  // Type 'null' is not assignable to type 'string'

  const toggleMode = () => {
    localStorage.setItem('Mode', !darkMode)
    setDarkMode(!darkMode);
  };

  return (
    <GlobalThemeContext.Provider value={{ darkMode, setDarkMode, toggleMode }}>
      {children}
    </GlobalThemeContext.Provider>
  );
};

Your code does almost work, yet there is no setting of the item from the localstorage:

import { createContext, useState } from "react";

export interface TypeContext {
  darkMode: true | false;
  setDarkMode: React.Dispatch<React.SetStateAction<boolean>>;
  toggleMode: () => void;
}

export interface TypeChildrenProps {
  children: JSX.Element;
}

export const GlobalThemeContext = createContext<TypeContext>({
  darkMode: false,
  setDarkMode: () => {},
  toggleMode: () => {},
});

export const ThemeContextProvider = ({ children }: TypeChildrenProps) => {
//this will throw an error if it isn't JSON, keep that in mind!  
const [darkMode, setDarkMode] = useState<object | array | null>(JSON.parse(localStorage.getItem('Mode'));

  const toggleMode = () => {
    localstorage.setItem('Mode', YOUR_VALUE)
    setDarkMode(dm => !dm);
  };

  return (
    <GlobalThemeContext.Provider value={{ darkMode, setDarkMode, toggleMode }}>
      {children}
    </GlobalThemeContext.Provider>
  );
};

Ask yourself if it is necessary to have the Mode as JSON. Maybe a boolean will do just fine – that would take away the possible parsing error.

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Reactjs – How can i save dark light mode in local storage with typescript?

Answers