DNA pairing using if else loop..plz correct any mistakes

function pairElement(str) {
  // Return each strand as an array of two elements, the original and the pair.
  var paired = [];

  // use if statement to check 
  var search = function(char) {
 paired.push(['A', 'T']);

 else if(char=='T'){
  paired.push(['T', 'A']);
   }else if(char=='C'){
        paired.push(['C', 'G']);
    else if  (char=='G'){
         paired.push(['G', 'C']);
  // Loops through the input and pair.
  for (var i = 0; i < str.length; i++) {

  return paired;

I cleaned up your code.
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See this post for details.