How I built a clean Social Media Caption Formatter in Vanilla JS

#javascript #webdev #productivity #opensource

As developers and creators, we know the pain of crafting the perfect social media caption, only to have Instagram or LinkedIn ruin the line breaks and formatting when published. I wanted a fast, offline tool to clean and format text, so I built a Caption Formatter.

The Approach

I built this using 100% Vanilla JS. There are no server calls, so your drafts and unreleased content stay completely private in your browser.

Here is a quick look at how the core logic handles zero-width spaces to force clean line breaks on stubborn platforms:

function formatCaption(inputText) {
    // Replace standard double line breaks with a zero-width space
    // to force platforms like Instagram to respect the spacing.
    const zeroWidthSpace = '\u2063';

    let formattedText = inputText.replace(/\n\n/g, `\n${zeroWidthSpace}\n`);

    // Additional cleaning for extra whitespace
    formattedText = formattedText.trim();

    return formattedText;
}