问如何避免堆内存不足？

EN

const Nightmare = require('nightmare');
const nightmare = Nightmare({show: true});


const LinguaURL = "";
const NumberOfMine = "";
const PwdOfMine = "";

var i,j = -1;
var selection, progress;
var radioSelect = -1;

function main() {
  nightmare
    .goto(LinguaURL)
    .wait(1000)
    .type("input[type='text']", NumberOfMine)
    .type("input[type='password']", PwdOfMine)
    .click("input[type='submit']")
    .wait(5000)
    .click('a[href="javascript:document.Study.submit()"]')
    .wait(3000)
    .click("input[type='button']")
    .wait(3000);

    for(i = 3;i<43;i++){
      nightmare
        .click('a[onclick="unit_view_page(\''+i.toString()+'\');"]');
        while(true){
          j++;

          if(j % 4 == 0){
          nightmare
            .click('input[onclick="select_unit(\'drill\', \''+(1833+j).toString()+'\', \'\');"]')
            .wait(1000);

          while(true){
            radioSelect++;

            nightmare
              .click('input[id="answer_0_' + radioSelect.toString() +'"]')
              .wait(1000)
              .click('input[id="ans_submit"]')
              .wait(1000)
              .evaluate(function (){
                 return selection = document.querySelector('.btn btn-answer-view form-font-size');
              })
              .evaluate(function (){
                return progress = document.querySelector('btn btn-next-problem form-font-size');
              });

              if(selection == null && progress == null)break;

              if(selection != null){
                continue;
              }else{
                nightmare
                  .click('input[class="btn btn-next-problem form-font-size"]');
                continue;
              }
          }
          if((j + 1) % 10 == 0)break;
          }
        }
      }
      nightmare
        .wait(100)
        .end()
        .then(console.log);
}

main();