useTheme Custom Hook: Maintain Standard Theme throughout the app

While working on a project, I found myself needing to use the same theme throughout the app. I wanted to be able to change the theme in one place and have it update everywhere. Also I don't want to remember the color codes of theme used in app.

To get rid of this problem, I created a custom React Hook useTheme. This hook will return the theme object and a function to update the theme. The theme object will be updated in all the components that use this hook.

Will cover this in detail with 3 main parts:

1. Theme Object
2. Custom Hook
3. Usage

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1. Theme Object

The theme object will have the following properties:

1. Colors

• primaryColor
• secondaryColor
• backgroundColor
• borderColor

2. Current Theme

• dark or light

3. Toggle Theme Function

• This function will toggle the theme between dark and light

NOTE: These 3 properties is just for an example. You can add more properties to the theme object.

The theme object will be updated in all the components using this hook. So, the theme will be maintained throughout the app. These will ensure that the theme is consistent throughout the app.

const lightColors = {
    primary: '#101010',
    secondary: '#7f7f7f',
    background: '#efefef',
    border: '#303030',
}

const darkColors = {
    primary: '#efefef',
    secondary: '#7f7f7f',
    background: '#101010',
    border: '#b0b0b0',
}

---

2. Custom Hook

React hooks are functions that let you hook into React state and lifecycle features from function components. You can read more about React Hooks here.

You can create a custom hook by using the use prefix and the name of the hook. For example, here useTheme is a custom hook. The custom hook will return the theme object and a function to update the theme. Here is the code for the custom hook:

const useTheme = () => {
    const [theme, setTheme] = useState('dark')

    const toggleTheme = () => {
        const nextTheme = theme === 'dark' ? 'light' : 'dark'
        setTheme(nextTheme)
    }

    const colors = theme === 'dark' ? darkColors : lightColors

    return { colors, currentTheme: theme, toggleTheme }
}

---

3. Usage

Now, we can use this custom hook in any functional component. Here is an example of how to use this hook in an App component:

import React from 'react'
import { useTheme } from './useTheme'

const App = () => {
        // get required properties from hook
    const { colors, currentTheme, toggleTheme } = useTheme()

    return (
        <div
            style={{
                backgroundColor: colors.background,
                color: colors.primary,
                padding: '1rem',
            }}
        >
            <h1>Custom Hook</h1>
            <p>Current Theme: {currentTheme}</p>
            <button onClick={toggleTheme}>Toggle Theme</button>
        </div>
    )
}

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Found Interesting? Try it out! 👨‍💻

You can try out the useTheme hook implementation in this CodeSandbox.

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Complete Code

Here is the complete code for the custom hook for your reference:

import { useState } from 'react'

const lightColors = {
    primary: '#101010',
    secondary: '#7f7f7f',
    background: '#efefef',
    border: '#303030',
}

const darkColors = {
    primary: '#efefef',
    secondary: '#7f7f7f',
    background: '#101010',
    border: '#b0b0b0',
}

const useTheme = () => {
    const [theme, setTheme] = useState('dark')

    const toggleTheme = () => {
        const nextTheme = theme === 'dark' ? 'light' : 'dark'
        setTheme(nextTheme)
    }

    const colors = theme === 'dark' ? darkColors : lightColors

    return { colors, currentTheme: theme, toggleTheme }
}

export default useTheme

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Closing Comments 👋

In this article, we learned how to create a custom hook to maintain the theme throughout the app. We also saw the usage of custom hook in any component. 👨‍💻

Comment below which custom hook you want to learn next. 💬

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Rushi Patel, Signing Off! 😊