babel-core/lib/babel/transformation/transformers/validation/no-for-in-of-assignment.js

Turn ES6 code into readable vanilla ES5 with source maps

"use strict";

var messages = require("../../../messages");
var t        = require("../../../types");

exports.check = t.isFor;

exports.ForInStatement =
exports.ForOfStatement = function (node, parent, scope, file) {
  var left = node.left;
  if (t.isVariableDeclaration(left)) {
    var declar = left.declarations[0];
    if (declar.init) throw file.errorWithNode(declar, messages.get("noAssignmentsInForHead"));
  }
};