Bash if seemingly working differently in functions?

Im not experienced with bash, but i seem to run into some random gotchas all the time when working on my scripts...

INPUT=""

input() {
    read -n 1 -p ":" INPUT
}

console() {
    if [[ $INPUT == "1" ]]; then
        hideMenu
        menu1
    elif [[ $INPUT == "2" ]]; then
        hideMenu
        menu2
    elif [[ $INPUT == "3" ]]; then
        hideMenu
        menu3
    elif [[ $INPUT == "menu" ]]; then
        showMenu
    elif [[ $INPUT == "q" ]]; then
        quit
    fi
}

This code works. it will read the input and then act according.

Then i have seemingly same thing in different file

J_INPUT=""

j_input() {
    read -n 1 -p ":" J_INPUT
}

console() {
    if [ $J_INPUT = "l"]; then
        CURR_PAGE=$((CURR_PAGE + 1))
    elif [ $J_INPUT = "j"]; then
        CURR_PAGE=$((CURR_PAGE - 1))
    elif [ $J_INPUT = "asd"]; then
        CURR_PAGE=$((CURR_PAGE + 1))
    fi
}

This however will not run for some reason. Also if i now try to use [[ ]] bash will throw an syntax error ?

What is wrong here? why cant i use the same syntax? what does [[ ]] valuate ?

Thanks.