Madars Bišs
May 25, 2023 ⋅ 9 min read

Building a React code editor and syntax highlighter from scratch

Madars Bišs Madars Bišs (aka Madza) is a technical writer. In his spare time, he loves to explore new topics and contribute to open-source web development.

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2 Replies to "Building a React code editor and syntax highlighter from scratch"

  1. I found a few problems with the code above. First, in your App.js file, when you define the constants defaultLanguage and defaultTheme, you start each with and end with but the ending tag should be . Oddly, without that fix, I get a syntax error on the word 'const' inside the App() function. I only figured out the problem by initially commenting out the definitions of defaultLanguage and defaultTheme, which made the error go away. Secondly, in index.js you apparently need to add "import React from 'react';" at the top, else you get a "React is not defined" error.

  2. There are few errors in the code, I would like to correct those.

    The default value of theme and language doesn’t work, it’s undefined. You need to write those as
    const defaultLanguage = “javascript” || Object.keys(languages).sort()[0];
    const defaultTheme = “atomOneDark” || Object.keys(themes).sort()[0];

    and in the dropdown.jsx defaultlanguage is never used , modify the code like this. We have only added a if/else condition to check if dropdown component is selected for theme or language change.

    export const Dropdown = ({ defaultLanguage ,defaultTheme, onChange, data }) => {
    const defaultValue = defaultTheme ? defaultTheme : defaultLanguage;
    return (

    .map((item, index) => {
    return (





    Thankyouh thankyouhhh so much for this amazing blog, very easy to understand and follow through. I’ll check your other blogs too. Thankyouh again, good work!

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