findemo/src/findEmo.js

library to find emoji from string and Convert Emoji to UTF and UTF to emoji

let emoRegexString = "(?:[\u2700-\u27bf]|(?:\ud83c[\udde6-\uddff]){2}|[\ud800-\udbff][\udc00-\udfff]|[\u0023\u002a\u0030-\u0039]\ufe0f?\u20e3|\u3299|\u3297|\u303d|\u3030|\u24c2|\ud83c[\udd70-\udd71]|\ud83c[\udd7e-\udd7f]|\ud83c\udd8e|\ud83c[\udd91-\udd9a]|\ud83c[\udde6-\uddff]|[\ud83c\ude01-\ude02]|\ud83c\ude1a|\ud83c\ude2f|[\ud83c\ude32-\ude3a]|[\ud83c\ude50-\ude51]|\u203c|\u2049|[\u25aa-\u25ab]|\u25b6|\u25c0|[\u25fb-\u25fe]|\u00a9|\u00ae|\u2122|\u2139|\ud83c\udc04|[\u2600-\u26FF]|\u2b05|\u2b06|\u2b07|\u2b1b|\u2b1c|\u2b50|\u2b55|\u231a|\u231b|\u2328|\u23cf|[\u23e9-\u23f3]|[\u23f8-\u23fa]|\ud83c\udccf|\u2934|\u2935|[\u2190-\u21ff])";
let emoRegex = new RegExp(emoRegexString);

function findEmoji(str) {
    let emoArr = [];
    for (let i = 0; i < str.length; i++) {
        let charPair = str.substring(i, i + 2);
        if (charPair.charAt(0) === " ") continue;
        let result = RegExp(emoRegex).test(charPair);
        if (result) {
            // to remove � unwanted emoji. start and end value of � emoji
            let strtCode = 55296;
            let endCode = 57343;
            let charCodeValue = charPair.codePointAt(0);
            if (!((charCodeValue >= strtCode) && (charCodeValue <= endCode))) {

                let emoLength = String.fromCodePoint(charCodeValue).length;
                let emo = {
                    position: [],
                    emoChar: null
                };
                if (emoLength > 1) {
                    emo.position.push(i);
                    emo.position.push(i + 1);
                    emo.emoChar = charPair;
                    emo.utf = emoToUtf(charPair);
                } else {
                    let reResult = RegExp(emoRegex).test(charPair.charAt(0));
                    if (reResult === false) {
                        continue;
                    } else {
                        emo.position.push(i);
                        emo.emoChar = charPair.charAt(0);
                        emo.utf = emoToUtf(charPair.charAt(0));
                    }

                }
                emoArr.push(emo)
            }
        }
    }
    let jsonObj = new Object();
    jsonObj.emos = emoArr;
    return jsonObj;
}

function emoToUtf(emo) {

    var comp;
    if (emo.length === 1) {
        comp = emo.charCodeAt(0);
    }
    comp = (
        (emo.charCodeAt(0) - 0xD800) * 0x400
        + (emo.charCodeAt(1) - 0xDC00) + 0x10000
    );
    if (comp < 0) {
        comp = emo.charCodeAt(0);
    }
    return comp.toString("16");
}

function utfToEmo(utfChar) {
   return String.fromCodePoint(parseInt (utfChar, 16))
}

module.exports ={
    findEmoji,
    emoToUtf,
    utfToEmo
}