Backend Developer

first take an empty array like:-
let tracer = []
start the loop on the string length that is given by params
for(let i=0;i < string.length; i++)
then we can check that the next bracket side by side are same or not or have different bracket so start with if condition
braces[i] === "(" || braces[i] === "{" || braces[i] === "["

just check like this in if condition and then push tracer.push(braces[i])

or else just check length === 0 then return false directly
and store the last value that is in the string so we can check for other condition
let lastValue = tracer[tracer.length-1]
then check condition for closing bracket 
(braces[i] === ']' && lastValue === '[') || (braces[i] === '}' && lastValue === '{') || (braces[i] === ')' && lastValue === '('. )

and then pop if condition get true
tracer.pop()
or else break;


this is how we can do this in javascript , I am adding the whole solution

Tip 1 : Learn all the basic of sql so you can answer them properly
Tip 2 : The three table joins I do was similar to this but he asked me to add more condition later
select s_name, score, status, address_city, 
email_id, accomplishments from student s, 
marks m, details d where s.s_id = m.s_id and 
m.school_id = d.school_id;
Tip 3 : Prepare yourself for javascript question too he asked all the basic definition and logic over javascript