Trigger emoji box on :: from the tweet modal text input.

main.js

// hit :: two times to have emoji popup open
let keystrokes = [];
const TARGET_EMOJI_POPUP_ON = ['::']
const LETTERS = [
    'A', 'B', 'C', 'D',
    'E', 'F', 'G', 'H',
    'I', 'J', 'K', 'L',
    'M', 'N', 'O', 'P',
    'Q', 'R', 'S', 'T',
    'U', 'V', 'W', 'X',
    'Y', 'Z'
]
const FORBIDEN_STROKES = [
    'Shift',
    'Backspace',
    'CapsLock',
    'WakeUp',
    'Alt',
    'Control',
    ...LETTERS,
    ...LETTERS.map(e => e.toLowerCase())
]

// Twitter DOM elements
const tweetInput = document.querySelectorAll('div.public-DraftStyleDefault-block')[0]
const emojiButton = document.querySelectorAll('div[aria-label="Add emoji"]')[0]

if (typeof emojiButton === "undefined"){
    alert("To use the emoji text, open a modal to tweet")
}else{
    document.addEventListener('keydown', (event) => {

        if (FORBIDEN_STROKES.indexOf(event.key) === -1){

            if(keystrokes.length == 2) keystrokes.shift();

            keystrokes.push(event.key);

            if (
                keystrokes.length == 2 &&
                keystrokes[0] == keystrokes[1] &&
                TARGET_EMOJI_POPUP_ON.indexOf(keystrokes.join('')) !== -1
            ){
                // we want to delete our ::
                for (var i=0; i < 2; i++)
                    window.dispatchEvent(
                        new KeyboardEvent('keydown', {
                            key: "Backspace",
                        })
                    );

                // we open the emoji popUp
                emojiButton.click();

                // we wait for the popUp of the emoji to be opened
                setTimeout(() => {
                    [...document.querySelectorAll(
                        '#emoji_picker_categories_dom_id > div[role="option"]'
                    )].forEach(
                        el => el.addEventListener(
                            'click', () => {
                                // we close the emoji popUp by clicking again
                                emojiButton.click();
                            }
                    ))
                }, 1000)
                // we click on the select messsage to search emojis
                keystrokes = [];
            }
        }
    });

}