prepack/lib/evaluators/IfStatement.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.evaluate = evaluate;

var _completions = require("../completions.js");

var _realm = require("../realm.js");

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

var _environment = require("../environment.js");

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

var _invariant = _interopRequireDefault(require("../invariant.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 */
function evaluate(ast, strictCode, env, realm) {
  // 1. Let exprRef be the result of evaluating Expression
  let exprRef = env.evaluate(ast.test, strictCode); // 2. Let exprValue be ToBoolean(? GetValue(exprRef))

  let exprValue = _singletons.Environment.GetConditionValue(realm, exprRef);

  if (exprValue instanceof _index.ConcreteValue) {
    let stmtCompletion;

    if (_singletons.To.ToBoolean(realm, exprValue)) {
      // 3.a. Let stmtCompletion be the result of evaluating the first Statement
      stmtCompletion = env.evaluateCompletion(ast.consequent, strictCode);
    } else {
      if (ast.alternate) {
        // 4.a. Let stmtCompletion be the result of evaluating the second Statement
        stmtCompletion = env.evaluateCompletion(ast.alternate, strictCode);
      } else {
        // 3 (of the if only statement). Return NormalCompletion(undefined)
        stmtCompletion = realm.intrinsics.undefined;
      }
    } // 5. Return Completion(UpdateEmpty(stmtCompletion, undefined)
    //if (stmtCompletion instanceof Reference) return stmtCompletion;


    (0, _invariant.default)(!(stmtCompletion instanceof _environment.Reference));
    stmtCompletion = (0, _index2.UpdateEmpty)(realm, stmtCompletion, realm.intrinsics.undefined);

    if (stmtCompletion instanceof _completions.AbruptCompletion) {
      throw stmtCompletion;
    }

    (0, _invariant.default)(stmtCompletion instanceof _index.Value);
    return stmtCompletion;
  }

  (0, _invariant.default)(exprValue instanceof _index.AbstractValue);

  if (!exprValue.mightNotBeTrue()) {
    let stmtCompletion = env.evaluate(ast.consequent, strictCode);
    (0, _invariant.default)(!(stmtCompletion instanceof _environment.Reference));
    stmtCompletion = (0, _index2.UpdateEmpty)(realm, stmtCompletion, realm.intrinsics.undefined);

    if (stmtCompletion instanceof _completions.AbruptCompletion) {
      throw stmtCompletion;
    }

    (0, _invariant.default)(stmtCompletion instanceof _index.Value);
    return stmtCompletion;
  } else if (!exprValue.mightNotBeFalse()) {
    let stmtCompletion;
    if (ast.alternate) stmtCompletion = env.evaluate(ast.alternate, strictCode);else stmtCompletion = realm.intrinsics.undefined;
    (0, _invariant.default)(!(stmtCompletion instanceof _environment.Reference));
    stmtCompletion = (0, _index2.UpdateEmpty)(realm, stmtCompletion, realm.intrinsics.undefined);

    if (stmtCompletion instanceof _completions.AbruptCompletion) {
      throw stmtCompletion;
    }

    (0, _invariant.default)(stmtCompletion instanceof _index.Value);
    return stmtCompletion;
  } else {
    (0, _invariant.default)(exprValue instanceof _index.AbstractValue);
    return realm.evaluateWithAbstractConditional(exprValue, () => realm.evaluateNodeForEffects(ast.consequent, strictCode, env), () => ast.alternate ? realm.evaluateNodeForEffects(ast.alternate, strictCode, env) : (0, _realm.construct_empty_effects)(realm));
  }
}
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