How to join two google sheets tables in app script by comparing a foreign key

Question

Lets say we have two tables in two sheets

sheet - NAME

Name	id
Alex	1
Christine	2

sheet - AGE

id	age
1	20
2	25

is there a way to get the following table in to a third sheet using appscripts without manually iterating through each row?

Name	id	age
Alex	1	20
Christine	2	25

I tried iterating through tables and joining, but the most of the parts of the app script code cannot be generalised to other scenarios.

Answer 1

If the id is always aligned by row (as in the example data).

=query({query({Name!A1:B},"select Col1, Col2 where Col1 is not null"),query({Age!A1:B},"select Col1, Col2 where Col1 is not null")},"select Col1, Col2, Col4 where Col2 = Col3")

---

If the id is not aligned by row.

=FILTER({A1:A,B1:B, vlookup(B1:B,D1:E,2,0)},A1:A<>"")

h/t : @MaxMakhrov How to join tables using Query or Vlookup

Name

Age

Results

Answer 2

Alternate Solution

You could iterate through these tables using the JavaScript Array map() method like this:

function sampleJoinTables(array1,array2){
  var result = array1.map(x => array2.map(y => y[0] === x[1] ? [x[0],x[1],y[1]] : null).filter(z => z).flat());
  return result;
}

Sample