for (let token of acorn.tokenizer(str)) {
  // iterate over the tokens
}

// transform code to array of tokens:
var tokens = [...acorn.tokenizer(str)];

function rename(code, tokenTo, tokenFrom) {

  

  //...
try {
    ast = acorn.parse(code, {
      ecmaVersion: 11,
      ranges: true,
      allowReturnOutsideFunction: true
    });
  } catch(err) {
    // this should probably log something and/or exit violently
    return code;
  }

  

  //...
}

const acornAst = recast.parse(source, {
  parser: {
    parse(source) {
      return require("acorn").parse(source, {
        // additional options
      });
    }
  }
});

let acorn = require("acorn");
console.log(acorn.parse("1 + 1", {ecmaVersion: 2020}));

var acorn = require("acorn");
var jsx = require("acorn-jsx");
var JSXParser = acorn.Parser.extend(jsx());
JSXParser.parse("foo(<bar/>)", {ecmaVersion: 2020});