function foo takes unit u returns boolean
    return UnitHasBuffBJ ( u, 'B000' ) //Вместо B000 - нужный бафф
endfunction

function foo takes nothing returns integer
    local integer array b
    local unit u
    local integer i = 0
    set b [0] = 'B000'
    set b [1] = 'B001'
    set b [2] = 'B002'
    loop    
        exitwhen i > 2
        if UnitHasBuffBJ ( u, b[i] ) then 
            return i
        endif
        set i = i + 1
    endloop
endfunction

function UnitHasBuffBJ takes unit whichUnit, integer buffcode returns boolean
    return (GetUnitAbilityLevel(whichUnit, buffcode) > 0)
endfunction