Eval Gotcha

eval.js

var x = 'global';

function indirectEval() {
  'use strict';
  var x = 'local';
  
  console.log(eval('x')); // Local

  // Call eval in a different way
  console.log(eval.call(null, 'x')); // global
  console.log(window.eval('x')); // global
  console.log((1, eval)('x')); // global (1)

  // Store eval somewhere else
  var xeval = eval;
  console.log(xeval('x')); // global
  var obj = { eval: eval };
  console.log(obj.eval('x')); // global
}

indirectEval();

function strictFunc() {
  'use strict';

  var code = '(function () { return this }())';
  var result = eval.call(null, code);
  console.log(result !== undefined); // true, sloppy mode
}