huir is right,"uir" is a retroflexed final(儿化音),Apart from being a syllable by itself,the final "er" often blends with the syllable preceding it.this is known as the restroflexed final.In writing "r" is added to the blended syllable and 儿to the character standing for such retroflexed,e.g. nǎr哪儿（where） hope it can help you a little bit~ and people in nouth of china often use "retroflexed final",southerners prefer to say 一会（yi hui） instead of 一会儿(yi huir)

一会(儿)前 yi hui(r) qian

That phrase is 一会儿前。会=hui, 儿=r huir=会儿。 Actually, it's also the first time I see this kind of pinyin.儿's pinyin should be 'er'. By the way, 儿 is a modal particle, in some Chinese regional accent, it is widely used like bejing accent. And in some cases, it makes the sentence of phrase more natural.

"huir“actually means 会儿. in chinese we have “'儿话音", when you speak "儿话音" you put "r" behind pinyin, for example:"huar","nar","mingr"

Actually what is pronounced like "huir" is made of two characters "hui" and "er" and not one character. The same is true for na er (pronounced nar). However, in many parts of China (specially in Shanghai) people tend to ignore the "er" part and just say yi hui (in the case of na'er and zh'er, they just use the alternative form of "na li" and " zhe li" ).