prepack/lib/evaluators/ArrayExpression.js

Execute a JS bundle, serialize global state and side effects to a snapshot that can be quickly restored.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = _default;

var _index = require("../values/index.js");

var _index2 = require("../methods/index.js");

var _invariant = _interopRequireDefault(require("../invariant.js"));

var _iterator = require("../methods/iterator.js");

var _singletons = require("../singletons.js");

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * Copyright (c) 2017-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

/*  strict-local */
// ECMA262 2.2.5.3
function _default(ast, strictCode, env, realm) {
  // 1. Let array be ArrayCreate(0).
  let array = _singletons.Create.ArrayCreate(realm, 0); // 2. Let len be the result of performing ArrayAccumulation for ElementList with arguments array and 0.


  let elements = ast.elements || [];
  let len = elements.length;
  let nextIndex = 0;

  for (let i = 0; i < len; i++) {
    let elem = elements[i];

    if (!elem) {
      nextIndex++;
      continue;
    } // ECMA262 12.2.5.2


    if (elem.type === "SpreadElement") {
      // 1. Let spreadRef be the result of evaluating AssignmentExpression.
      let spreadRef = env.evaluate(elem.argument, strictCode); // 2. Let spreadObj be ? GetValue(spreadRef).

      let spreadObj = _singletons.Environment.GetValue(realm, spreadRef); // 3. Let iterator be ? GetIterator(spreadObj).


      let iterator = (0, _index2.GetIterator)(realm, spreadObj); // 4. Repeat

      while (true) {
        // a. Let next be ? IteratorStep(iterator).
        let next = (0, _iterator.IteratorStep)(realm, iterator); // b. If next is false, return nextIndex.

        if (next === false) break; // c. Let nextValue be ? IteratorValue(next).

        let nextValue = (0, _iterator.IteratorValue)(realm, next); // d. Let status be CreateDataProperty(array, ToString(ToUint32(nextIndex)), nextValue).

        let status = _singletons.Create.CreateDataProperty(realm, array, new _index.StringValue(realm, nextIndex++ + ""), nextValue); // e. Assert: status is true.


        (0, _invariant.default)(status === true); // f. Let nextIndex be nextIndex + 1.
      }
    } else {
      // Redundant steps.
      // 1. Let postIndex be the result of performing ArrayAccumulation for ElementList with arguments array and nextIndex.
      // 2. ReturnIfAbrupt(postIndex).
      // 3. Let padding be the ElisionWidth of Elision; if Elision is not present, use the numeric value zero.
      // 4. Let initResult be the result of evaluating AssignmentExpression.
      let initResult = env.evaluate(elem, strictCode); // 5. Let initValue be ? GetValue(initResult).

      let initValue = _singletons.Environment.GetValue(realm, initResult); // 6. Let created be CreateDataProperty(array, ToString(ToUint32(postIndex+padding)), initValue).


      let created = _singletons.Create.CreateDataProperty(realm, array, new _index.StringValue(realm, nextIndex++ + ""), initValue); // 7. Assert: created is true.


      (0, _invariant.default)(created === true, "expected data property creation");
    }
  } // Not necessary since we propagate completions with exceptions.
  // 3. ReturnIfAbrupt(len).
  // 4. Perform Set(array, "length", ToUint32(len), false).


  _singletons.Properties.Set(realm, array, "length", new _index.NumberValue(realm, nextIndex), false); // 5. NOTE: The above Set cannot fail because of the nature of the object returned by ArrayCreate.
  // 6. Return array.


  return array;
}
//# sourceMappingURL=ArrayExpression.js.map