export function merge(…sets:Array<string>):string {

if (sets.length > 1) {
        sets[0] = sets[0].slice(0, -1);
        const xl = sets.length - 1;
        for (let x = 1; x < xl; ++x) {
                sets[x] = sets[x].slice(1, -1);
        }
        sets[xl] = sets[xl].slice(1);
        return sets.join('');
} else {
        return sets[0];
}

}

export function subexp(str:string):string {

return "(?:" + str + ")";

}

export function typeOf(o:any):string {

return o === undefined ? "undefined" : (o === null ? "null" : Object.prototype.toString.call(o).split(" ").pop().split("]").shift().toLowerCase());

}

export function toUpperCase(str:string):string {

return str.toUpperCase();

}

export function toArray(obj:any):Array<any> {

return obj !== undefined && obj !== null ? (obj instanceof Array ? obj : (typeof obj.length !== "number" || obj.split || obj.setInterval || obj.call ? [obj] : Array.prototype.slice.call(obj))) : [];

}

export function assign(target: object, source: any): any {

const obj = target as any;
if (source) {
        for (const key in source) {
                obj[key] = source[key];
        }
}
return obj;

}