Using javascript unique Generate Id

generateId.js

function generateId () {
	const charset = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890-';
    var chars = [];
    
    for (var i = 0; i < 7; i++) {
    	chars[i] = charset[Math.floor(Math.random() * charset.length)]
    }
    
    return chars.join('');
}

// Java
public static String generateId() {
        String charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890-";
        StringBuilder s = new StringBuilder();
        for (int i = 0; i < 7; i++) {
            s.append(charset.charAt((int) (Math.floor(Math.random() * charset.length()))));
        }
        return s.toString();
    }