Function to pré generate messageId for WhatsApp Web APIs

generateWhatsAppMsgId.ts

/**
* Function to pre generate messageId for WhatsApp WEB APIs
* For groups is necessary send deviceNumber
**/

export function generateWhatsAppMsgId (to: string, deviceNumber?: string) {
    if (/^\d+@c.us$/.test(parseWid(to))) {
        return `true_${parseWid(to)}_${newId()}`
    } else {
        if(!deviceNumber) throw new Error("Please, send device number for send msg to groups");
        return `true_${parseWid(to)}_${newId()}_${parseWid(deviceNumber)}`
    }
}

function parseWid(number: string): string {
    if(/^\d+@c.us$/.test(number) || /^\d+-\d+@g.us$/.test(number))
        return number;
    else if(/^\d+$/.test(number))
        return number + "c.us";
    else if(/^\d+-\d+$/.test(number))
        return number + "g.us";
    else
        throw new Error("Send the whatsapp number correctly");
}


function newId(): string {
    const t = new Uint8Array(8);
    const randomHex =  self.crypto.getRandomValues(t);
    const parsed = parseHex(randomHex);

    return '3EB0' + parsed;
}

function parseHex(e: any) {
    const arr = [48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70];
    const t = [];
    for (let r = 0; r < e.length; r++) {
      const i = e[r];
      t.push(arr[i >> 4], arr[15 & i]);
    }
    return String.fromCharCode.apply(String, t);
}