src/core/utils.js
function mergeTags(base, addition) {
    Array.prototype.push.apply(base, addition);
    return base;
}
function mergeTags(base, addition) {
    Array.prototype.push.apply(base, addition);
    return base;
}
function mergeTags ( base , addition ) { Array . prototype . push . apply ( base , addition ) ; return base ; }
Modify base array adding all tag from addition
Modify base array adding all tag from addition