prepack/lib/intrinsics/ecma262/parseInt.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 _singletons = require("../../singletons.js");

/**
 * 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 ToDigit(ch) {
  if (ch >= "0" && ch <= "9") {
    return ch.charCodeAt(0) - "0".charCodeAt(0);
  } else if (ch >= "A" && ch <= "Z") {
    return 10 + ch.charCodeAt(0) - "A".charCodeAt(0);
  } else if (ch >= "a" && ch <= "z") {
    return 10 + ch.charCodeAt(0) - "a".charCodeAt(0);
  }

  return undefined;
}

function _default(realm) {
  return new _index.NativeFunctionValue(realm, "parseInt", "parseInt", 2, (context, [string, radix]) => {
    // 1. Let inputString be ? ToString(string).
    let inputString = _singletons.To.ToStringPartial(realm, string); // 2. Let S be a newly created substring of inputString consisting of the first code unit that is not a StrWhiteSpaceChar and all code units following that code unit. (In other words, remove leading white space.) If inputString does not contain any such code unit, let S be the empty string.


    let S = inputString.trim(); // 3. Let sign be 1.

    let sign = 1; // 4. If S is not empty and the first code unit of S is 0x002D (HYPHEN-MINUS), let sign be -1.

    if (S !== "" && S.charAt(0) === "-") sign = -1; // 5. If S is not empty and the first code unit of S is 0x002B (PLUS SIGN) or 0x002D (HYPHEN-MINUS), remove the first code unit from S.

    if (S !== "" && (S.charAt(0) === "-" || S.charAt(0) === "+")) S = S.substr(1); // 6. Let R be ? ToInt32(radix).

    let R = _singletons.To.ToInt32(realm, radix); // 7. Let stripPrefix be true.


    let stripPrefix = true; // 8. If R ≠ 0, then

    if (R !== 0) {
      // a. If R < 2 or R > 36, return NaN.
      if (R < 2 || R > 36) return realm.intrinsics.NaN; // b .If R ≠ 16, let stripPrefix be false.

      if (R !== 16) stripPrefix = false;
    } else {
      // 9. Else R = 0,
      // a. Let R be 10.
      R = 10;
    } // 10. If stripPrefix is true, then


    if (stripPrefix === true) {
      // a. If the length of S is at least 2 and the first two code units of S are either "0x" or "0X", remove the first two code units from S and let R be 16.
      if (S.length >= 2 && S.charAt(0) === "0" && (S.charAt(1) === "x" || S.charAt(1) === "X")) {
        S = S.substr(2);
        R = 16;
      }
    } // 11. If S contains a code unit that is not a radix-R digit, let Z be the substring of S consisting of all code units before the first such code unit; otherwise, let Z be S.


    let Z = "";

    for (let i = 0; i < S.length; ++i) {
      let digit = ToDigit(S.charAt(i));

      if (digit === undefined || digit >= R) {
        break;
      }

      Z = Z + S.charAt(i);
    } // 12. If Z is empty, return NaN.


    if (Z === "") return realm.intrinsics.NaN; // 13. Let mathInt be the mathematical integer value that is represented by Z in radix-R notation, using the letters A-Z and a-z for digits with values 10 through 35. (However, if R is 10 and Z contains more than 20 significant digits, every significant digit after the 20th may be replaced by a 0 digit, at the option of the implementation; and if R is not 2, 4, 8, 10, 16, or 32, then mathInt may be an implementation-dependent approximation to the mathematical integer value that is represented by Z in radix-R notation.)

    let mathInt = 0;

    for (let i = 0; i < Z.length; ++i) {
      mathInt = mathInt * R + (ToDigit(Z.charAt(i)) || 0);
    } // 14. If mathInt = 0, then


    if (mathInt === 0) {
      // a. If sign = -1, return -0.
      if (sign === -1) return realm.intrinsics.negativeZero; // b. Return +0.

      return realm.intrinsics.zero;
    } // 15. Let number be the Number value for mathInt.


    let number = Number(mathInt); // 5. Return sign × number.

    return new _index.NumberValue(realm, sign * number);
  }, false);
}
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