convert a prefix expression to infix expression using javaScript

Question

I am really struck with a question .

convert the below expression using javaScript

[ "AND", ["<", "var1", "var2"], [ "OR", [">", "var3", "var4"], ["==", "var5", "var6"] ]

to

var1 < val2 AND (var3 > val4 OR val5 == val6)

Sorry that, I dont have any more informations

Answer 1

try this recursive approach

var convert = function(arr) {
    if (typeof arr[0] == 'string' && arr[1] instanceof Array && arr[2] instanceof Array) {
        return ' (' + convert(arr[1]) + arr[0] + convert(arr[2]) + ') ';
    } else {
        return ' ' + arr[1] + ' ' + arr[0] + ' ' + arr[2] + ' ';
    }
}