Lady’s Gitweb - Pisces/blob - string.js

   1 // SPDX-FileCopyrightText: 2022, 2023, 2025 Lady <https://www.ladys.computer/about/#lady>
   2 // SPDX-License-Identifier: MPL-2.0
   3 /**
   4  * ⁌ ♓🧩 Piscēs ∷ string.js
   5  *
   6  * Copyright © 2022–2023, 2025 Lady [@ Ladys Computer].
   7  *
   8  * This Source Code Form is subject to the terms of the Mozilla Public
   9  * License, v. 2.0. If a copy of the MPL was not distributed with this
  10  * file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
  11  */
  12
  13 import {
  14   bind,
  15   call,
  16   completesNormally,
  17   createArrowFunction,
  18   createCallableFunction,
  19   identity,
  20 } from "./function.js";
  21 import {
  22   arrayIteratorFunction,
  23   stringIteratorFunction,
  24 } from "./iterable.js";
  25 import {
  26   defineOwnDataProperty,
  27   defineOwnProperties,
  28   getOwnPropertyDescriptors,
  29   objectCreate,
  30   setPropertyValues,
  31   setPrototype,
  32 } from "./object.js";
  33 import { sameValue, toLength, UNDEFINED } from "./value.js";
  34
  35 const PISCĒS = "♓🧩 Piscēs";
  36
  37 const RE = RegExp;
  38 const { prototype: rePrototype } = RE;
  39 const { prototype: arrayPrototype } = Array;
  40 const { prototype: stringPrototype } = String;
  41
  42 const { exec: reExec } = rePrototype;
  43
  44 export const {
  45   /**
  46    * A `RegExp´‐like object which only matches entire strings, and may
  47    * have additional constraints specified.
  48    *
  49    * Matchers are callable objects and will return true if they are
  50    * called with a string that they match, and false otherwise.
  51    * Matchers will always return false if called with nonstrings, altho
  52    * other methods like `::exec´ coerce their arguments and may still
  53    * return true.
  54    */
  55   Matcher,
  56 } = (() => {
  57   const { toString: reToString } = rePrototype;
  58   const getDotAll =
  59     Object.getOwnPropertyDescriptor(rePrototype, "dotAll").get;
  60   const getFlags =
  61     Object.getOwnPropertyDescriptor(rePrototype, "flags").get;
  62   const getGlobal =
  63     Object.getOwnPropertyDescriptor(rePrototype, "global").get;
  64   const getHasIndices =
  65     Object.getOwnPropertyDescriptor(rePrototype, "hasIndices").get;
  66   const getIgnoreCase =
  67     Object.getOwnPropertyDescriptor(rePrototype, "ignoreCase").get;
  68   const getMultiline =
  69     Object.getOwnPropertyDescriptor(rePrototype, "multiline").get;
  70   const getSource =
  71     Object.getOwnPropertyDescriptor(rePrototype, "source").get;
  72   const getSticky =
  73     Object.getOwnPropertyDescriptor(rePrototype, "sticky").get;
  74   const getUnicode =
  75     Object.getOwnPropertyDescriptor(rePrototype, "unicode").get;
  76   const getUnicodeSets =
  77     Object.getOwnPropertyDescriptor(rePrototype, "unicodeSets").get;
  78
  79   /**
  80    * The internal implementation of `Matcher´.
  81    *
  82    * ※ This class extends the identity function to enable the addition
  83    * of private fields to the callable matcher function it constructs.
  84    *
  85    * ※ This class is not exposed.
  86    */
  87   const Matcher = class extends identity {
  88     #constraint;
  89     #regExp;
  90
  91     /**
  92      * Constructs a new `Matcher´ from the provided source.
  93      *
  94      * If the provided source is a regular expression, then it must
  95      * have either the unicode flag set or the unicode sets flag set.
  96      * Otherwise, it is interpreted as the string source of a regular
  97      * expression with the unicode flag set.
  98      *
  99      * Other flags are taken from the provided regular expression
 100      * object, if any are present.
 101      *
 102      * A name for the matcher may be provided as the second argument.
 103      *
 104      * A callable constraint on acceptable inputs may be provided as a
 105      * third argument. If provided, it will be called with three
 106      * arguments whenever a match appears successful: first, the string
 107      * being matched, second, the match result, and third, the
 108      * `Matcher´ object itself. If the return value of this call is
 109      * falsey, then the match will be considered a failure.
 110      *
 111      * ☡ If the provided source regular expression uses nongreedy
 112      * quantifiers, it may not match the whole string even if a match
 113      * with the whole string is possible. Surround the regular
 114      * expression with `^(?:´ and `)$´ if you don¦t want nongreedy
 115      * regular expressions to fail when shorter matches are possible.
 116      */
 117     constructor(source, name = UNDEFINED, constraint = null) {
 118       super(
 119         ($) => {
 120           if (typeof $ !== "string") {
 121             // The provided value is not a string.
 122             return false;
 123           } else {
 124             // The provided value is a string.
 125             //
 126             // Set the `.lastIndex´ of the regular expression to 0, and
 127             // see if the first attempt at a match successfully matches
 128             // the whole string and passes the provided constraint (if
 129             // present).
 130             regExp.lastIndex = 0;
 131             const result = call(reExec, regExp, [$]);
 132             return result?.[0] === $
 133               && (constraint === null || constraint($, result, this));
 134           }
 135         },
 136       );
 137       const regExp = this.#regExp = (() => {
 138         if (completesNormally(() => call(reExec, source, [""]))) {
 139           // The provided source is a `RegExp´.
 140           if (
 141             !call(getUnicode, source, [])
 142             && !call(getUnicodeSets, source, [])
 143           ) {
 144             // The provided regular expression does not have a unicode
 145             // flag or unicode sets flag.
 146             throw new TypeError(
 147               `${PISCĒS}: Cannot create Matcher from non‐Unicode RegExp: ${source}`,
 148             );
 149           } else {
 150             // The provided regular expression has a unicode flag or
 151             // unicode sets flag.
 152             return new RE(source);
 153           }
 154         } else {
 155           // The provided source is not a `RegExp´.
 156           //
 157           // Create one using it as the source string.
 158           return new RE(`${source}`, "u");
 159         }
 160       })();
 161       if (constraint !== null && typeof constraint !== "function") {
 162         throw new TypeError(
 163           `${PISCĒS}: Cannot construct Matcher: Constraint is not callable.`,
 164         );
 165       } else {
 166         this.#constraint = constraint;
 167         return defineOwnProperties(
 168           setPrototype(this, matcherPrototype),
 169           {
 170             lastIndex: setPropertyValues(objectCreate(null), {
 171               configurable: false,
 172               enumerable: false,
 173               value: 0,
 174               writable: false,
 175             }),
 176             name: defineOwnDataProperty(
 177               objectCreate(null),
 178               "value",
 179               name != null
 180                 ? `${name}`
 181                 : `Matcher(${call(reToString, regExp, [])})`,
 182             ),
 183           },
 184         );
 185       }
 186     }
 187
 188     /** Gets whether the dot‐all flag is present on this `Matcher´. */
 189     get dotAll() {
 190       return call(getDotAll, this.#regExp, []);
 191     }
 192
 193     /**
 194      * Executes this `Matcher´ on the provided value and returns the
 195      * result if there is a match, or null otherwise.
 196      *
 197      * Matchers only match if they can match the entire value on the
 198      * first attempt.
 199      *
 200      * ☡ The match result returned by this method will be the same as
 201      * that passed to the constraint function—and may have been
 202      * modified by said function prior to being returned.
 203      */
 204     exec($) {
 205       const regExp = this.#regExp;
 206       const constraint = this.#constraint;
 207       const string = `${$}`;
 208       regExp.lastIndex = 0;
 209       const result = call(reExec, regExp, [string]);
 210       if (
 211         result?.[0] === string
 212         && (constraint === null || constraint(string, result, this))
 213       ) {
 214         // The entire string was matched and the constraint, if
 215         // present, returned a truthy value.
 216         return result;
 217       } else {
 218         // The entire string was not matched or the constraint returned
 219         // a falsey value.
 220         return null;
 221       }
 222     }
 223
 224     /**
 225      * Gets the flags present on this `Matcher´.
 226      *
 227      * ※ This needs to be defined because the internal `RegExp´ object
 228      * may have flags which are not yet recognized by ♓🧩 Piscēs.
 229      */
 230     get flags() {
 231       return call(getFlags, this.#regExp, []);
 232     }
 233
 234     /** Gets whether the global flag is present on this `Matcher´. */
 235     get global() {
 236       return call(getGlobal, this.#regExp, []);
 237     }
 238
 239     /**
 240      * Gets whether the has‐indices flag is present on this `Matcher´.
 241      */
 242     get hasIndices() {
 243       return call(getHasIndices, this.#regExp, []);
 244     }
 245
 246     /**
 247      * Gets whether the ignore‐case flag is present on this `Matcher´.
 248      */
 249     get ignoreCase() {
 250       return call(getIgnoreCase, this.#regExp, []);
 251     }
 252
 253     /**
 254      * Gets whether the multiline flag is present on this `Matcher´.
 255      */
 256     get multiline() {
 257       return call(getMultiline, this.#regExp, []);
 258     }
 259
 260     /** Gets the regular expression source for this `Matcher´. */
 261     get source() {
 262       return call(getSource, this.#regExp, []);
 263     }
 264
 265     /** Gets whether the sticky flag is present on this `Matcher´. */
 266     get sticky() {
 267       return call(getSticky, this.#regExp, []);
 268     }
 269
 270     /**
 271      * Gets whether the unicode flag is present on this `Matcher´.
 272      */
 273     get unicode() {
 274       return call(getUnicode, this.#regExp, []);
 275     }
 276
 277     /**
 278      * Gets whether the unicode sets flag is present on this `Matcher´.
 279      */
 280     get unicodeSets() {
 281       return call(getUnicodeSets, this.#regExp, []);
 282     }
 283   };
 284
 285   const matcherConstructor = Object.defineProperties(
 286     class extends RegExp {
 287       constructor(...args) {
 288         return new Matcher(...args);
 289       }
 290     },
 291     {
 292       name: defineOwnDataProperty(
 293         Object.create(null),
 294         "value",
 295         "Matcher",
 296       ),
 297       length: defineOwnDataProperty(Object.create(null), "value", 1),
 298     },
 299   );
 300   const matcherPrototype = defineOwnProperties(
 301     matcherConstructor.prototype,
 302     getOwnPropertyDescriptors(Matcher.prototype),
 303     {
 304       constructor: defineOwnDataProperty(
 305         Object.create(null),
 306         "value",
 307         matcherConstructor,
 308       ),
 309     },
 310   );
 311
 312   return { Matcher: matcherConstructor };
 313 })();
 314
 315 export const {
 316   /**
 317    * Returns the result of converting the provided value to A·S·C·I·I
 318    * lowercase.
 319    */
 320   asciiLowercase,
 321
 322   /**
 323    * Returns the result of converting the provided value to A·S·C·I·I
 324    * uppercase.
 325    */
 326   asciiUppercase,
 327 } = (() => {
 328   const {
 329     toLowerCase: stringToLowercase,
 330     toUpperCase: stringToUppercase,
 331   } = stringPrototype;
 332   return {
 333     asciiLowercase: ($) =>
 334       stringReplaceAll(
 335         `${$}`,
 336         /[A-Z]/gu,
 337         createCallableFunction(stringToLowercase),
 338       ),
 339     asciiUppercase: ($) =>
 340       stringReplaceAll(
 341         `${$}`,
 342         /[a-z]/gu,
 343         createCallableFunction(stringToUppercase),
 344       ),
 345   };
 346 })();
 347
 348 export const {
 349   /**
 350    * Returns an iterator over the codepoints in the string representation
 351    * of the provided value according to the algorithm of
 352    * `String::[Symbol.iterator]´.
 353    */
 354   characters,
 355
 356   /**
 357    * Returns an iterator over the code units in the string
 358    * representation of the provided value.
 359    */
 360   codeUnits,
 361
 362   /**
 363    * Returns an iterator over the codepoints in the string
 364    * representation of the provided value.
 365    */
 366   codepoints,
 367
 368   /**
 369    * Returns an iterator over the scalar values in the string
 370    * representation of the provided value.
 371    *
 372    * Codepoints which are not valid Unicode scalar values are replaced
 373    * with U+FFFD.
 374    */
 375   scalarValues,
 376 } = (() => {
 377   const generateCharacters = function* (character) {
 378     yield character;
 379   };
 380   const generateCodeUnits = function* (ucsCharacter) {
 381     yield getCodeUnit(ucsCharacter, 0);
 382   };
 383   const generateCodepoints = function* (character) {
 384     const { allowSurrogates } = this;
 385     const codepoint = getCodepoint(character, 0);
 386     yield allowSurrogates || codepoint <= 0xD7FF || codepoint >= 0xE000
 387       ? codepoint
 388       : 0xFFFD;
 389   };
 390
 391   const charactersIterator = stringIteratorFunction(
 392     generateCharacters,
 393     "String Character Iterator",
 394   );
 395   const codeUnitsIterator = arrayIteratorFunction(
 396     generateCodeUnits,
 397     "String Code Unit Iterator",
 398   );
 399   const codepointsIterator = stringIteratorFunction(
 400     bind(generateCodepoints, { allowSurrogates: true }, []),
 401     "String Codepoint Iterator",
 402   );
 403   const scalarValuesIterator = stringIteratorFunction(
 404     bind(generateCodepoints, { allowSurrogates: false }, []),
 405     "String Scalar Value Iterator",
 406   );
 407
 408   return {
 409     characters: ($) => charactersIterator(`${$}`),
 410     codeUnits: ($) => codeUnitsIterator(`${$}`),
 411     codepoints: ($) => codepointsIterator(`${$}`),
 412     scalarValues: ($) => scalarValuesIterator(`${$}`),
 413   };
 414 })();
 415
 416 /**
 417  * Returns the character at the provided position in the string
 418  * representation of the provided value according to the algorithm of
 419  * `String::codePointAt´.
 420  */
 421 export const getCharacter = ($, pos) => {
 422   const codepoint = getCodepoint($, pos);
 423   return codepoint == null
 424     ? UNDEFINED
 425     : stringFromCodepoints(codepoint);
 426 };
 427
 428 export const {
 429   /**
 430    * Returns the code unit at the provided position in the string
 431    * representation of the provided value according to the algorithm of
 432    * `String::charAt´, except that out‐of‐bounds values return
 433    * undefined in place of nan.
 434    */
 435   getCodeUnit,
 436
 437   /**
 438    * Returns a string created from the provided code units.
 439    *
 440    * ※ This is effectively an alias for `String.fromCharCode´, but
 441    * with the same error behaviour as `String.fromCodePoint´.
 442    *
 443    * ☡ This function throws an error if provided with an argument which
 444    * is not an integral number from 0 to FFFF₁₆ inclusive.
 445    */
 446   stringFromCodeUnits,
 447
 448   /**
 449    * Returns the result of catenating the string representations of the
 450    * provided values, returning a new string according to the algorithm
 451    * of `String::concat´.
 452    *
 453    * ※ If no arguments are given, this function returns the empty
 454    * string. This is different behaviour than if an explicit undefined
 455    * first argument is given, in which case the resulting string will
 456    * begin with `"undefined"´.
 457    */
 458   stringCatenate,
 459 } = (() => {
 460   const { fromCharCode } = String;
 461   const { charCodeAt, concat } = String.prototype;
 462   const {
 463     isInteger: isIntegralNumber,
 464     isNaN: isNan,
 465   } = Number;
 466
 467   return {
 468     getCodeUnit: ($, n) => {
 469       const codeUnit = call(charCodeAt, $, [n]);
 470       return isNan(codeUnit) ? UNDEFINED : codeUnit;
 471     },
 472     stringCatenate: Object.defineProperties(
 473       (...args) => call(concat, "", args),
 474       { name: { value: "stringCatenate" }, length: { value: 2 } },
 475     ),
 476     stringFromCodeUnits: Object.defineProperties(
 477       (...codeUnits) => {
 478         for (let index = 0; index < codeUnits.length; ++index) {
 479           // Iterate over each provided code unit and throw if it is
 480           // out of range.
 481           const nextCU = +codeUnits[index];
 482           if (
 483             !isIntegralNumber(nextCU) || nextCU < 0 || nextCU > 0xFFFF
 484           ) {
 485             // The code unit is not an integral number between 0 and
 486             // 0xFFFF; this is an error.
 487             throw new RangeError(
 488               `${PISCĒS}: Code unit out of range: ${nextCU}.`,
 489             );
 490           } else {
 491             // The code unit is acceptable.
 492             /* do nothing */
 493           }
 494         }
 495         return call(fromCharCode, UNDEFINED, codeUnits);
 496       },
 497       { name: { value: "stringFromCodeUnits" }, length: { value: 1 } },
 498     ),
 499   };
 500 })();
 501
 502 /**
 503  * Returns the codepoint at the provided position in the string
 504  * representation of the provided value according to the algorithm of
 505  * `String::codePointAt´.
 506  */
 507 export const getCodepoint = createCallableFunction(
 508   stringPrototype.codePointAt,
 509   { name: "getCodepoint" },
 510 );
 511
 512 /**
 513  * Returns the index of the first occurrence of the search string in
 514  * the string representation of the provided value according to the
 515  * algorithm of `String::indexOf´.
 516  */
 517 export const getFirstSubstringIndex = createCallableFunction(
 518   stringPrototype.indexOf,
 519   { name: "getFirstSubstringIndex" },
 520 );
 521
 522 /**
 523  * Returns the index of the last occurrence of the search string in the
 524  * string representation of the provided value according to the
 525  * algorithm of `String::lastIndexOf´.
 526  */
 527 export const getLastSubstringIndex = createCallableFunction(
 528   stringPrototype.lastIndexOf,
 529   { name: "getLastSubstringIndex" },
 530 );
 531
 532 /**
 533  * Returns the result of joining the provided iterable.
 534  *
 535  * If no separator is provided, it defaults to `","´.
 536  *
 537  * If a value is nullish, it will be stringified as the empty string.
 538  */
 539 export const join = (() => {
 540   const { join: arrayJoin } = arrayPrototype;
 541   const join = ($, separator) =>
 542     call(
 543       arrayJoin,
 544       [...$],
 545       [separator === UNDEFINED ? "," : `${separator}`],
 546     );
 547   return join;
 548 })();
 549
 550 /**
 551  * Returns a string created from the raw value of the tagged template
 552  * literal.
 553  *
 554  * ※ This is effectively an alias for `String.raw´.
 555  */
 556 export const rawString = createArrowFunction(String.raw, {
 557   name: "rawString",
 558 });
 559
 560 /**
 561  * Returns a string created from the provided codepoints.
 562  *
 563  * ※ This is effectively an alias for `String.fromCodePoint´.
 564  *
 565  * ☡ This function throws an error if provided with an argument which
 566  * is not an integral number from 0 to 10FFFF₁₆ inclusive.
 567  */
 568 export const stringFromCodepoints = createArrowFunction(
 569   String.fromCodePoint,
 570   { name: "stringFromCodepoints" },
 571 );
 572
 573 /**
 574  * Returns the result of splitting the provided value on Ascii
 575  * whitespace.
 576  */
 577 export const splitOnAsciiWhitespace = ($) =>
 578   stringSplit(stripAndCollapseAsciiWhitespace($), " ");
 579
 580 /**
 581  * Returns the result of splitting the provided value on commas,
 582  * trimming Ascii whitespace from the resulting tokens.
 583  */
 584 export const splitOnCommas = ($) =>
 585   stringSplit(
 586     stripLeadingAndTrailingAsciiWhitespace(
 587       stringReplaceAll(
 588         `${$}`,
 589         /[\n\r\t\f ]*,[\n\r\t\f ]*/gu,
 590         ",",
 591       ),
 592     ),
 593     ",",
 594   );
 595
 596 /**
 597  * Returns whether the string representation of the provided value ends
 598  * with the provided search string according to the algorithm of
 599  * `String::endsWith´.
 600  */
 601 export const stringEndsWith = createCallableFunction(
 602   stringPrototype.endsWith,
 603   { name: "stringEndsWith" },
 604 );
 605
 606 /**
 607  * Returns whether the string representation of the provided value
 608  * contains the provided search string according to the algorithm of
 609  * `String::includes´.
 610  */
 611 export const stringIncludes = createCallableFunction(
 612   stringPrototype.includes,
 613   { name: "stringIncludes" },
 614 );
 615
 616 /**
 617  * Returns the result of matching the string representation of the
 618  * provided value with the provided matcher according to the algorithm
 619  * of `String::match´.
 620  */
 621 export const stringMatch = createCallableFunction(
 622   stringPrototype.match,
 623   { name: "stringMatch" },
 624 );
 625
 626 /**
 627  * Returns the result of matching the string representation of the
 628  * provided value with the provided matcher according to the algorithm
 629  * of `String::matchAll´.
 630  */
 631 export const stringMatchAll = createCallableFunction(
 632   stringPrototype.matchAll,
 633   { name: "stringMatchAll" },
 634 );
 635
 636 /**
 637  * Returns the normalized form of the string representation of the
 638  * provided value according to the algorithm of `String::normalize´.
 639  */
 640 export const stringNormalize = createCallableFunction(
 641   stringPrototype.normalize,
 642   { name: "stringNormalize" },
 643 );
 644
 645 /**
 646  * Returns the result of padding the end of the string representation
 647  * of the provided value padded until it is the desired length
 648  * according to the algorithm of `String::padEnd´.
 649  */
 650 export const stringPadEnd = createCallableFunction(
 651   stringPrototype.padEnd,
 652   { name: "stringPadEnd" },
 653 );
 654
 655 /**
 656  * Returns the result of padding the start of the string representation
 657  * of the provided value padded until it is the desired length
 658  * according to the algorithm of `String::padStart´.
 659  */
 660 export const stringPadStart = createCallableFunction(
 661   stringPrototype.padStart,
 662   { name: "stringPadStart" },
 663 );
 664
 665 /**
 666  * Returns the result of repeating the string representation of the
 667  * provided value the provided number of times according to the
 668  * algorithm of `String::repeat´.
 669  */
 670 export const stringRepeat = createCallableFunction(
 671   stringPrototype.repeat,
 672   { name: "stringRepeat" },
 673 );
 674
 675 /**
 676  * Returns the result of replacing the string representation of the
 677  * provided value with the provided replacement, using the provided
 678  * matcher and according to the algorithm of `String::replace´.
 679  */
 680 export const stringReplace = createCallableFunction(
 681   stringPrototype.replace,
 682   { name: "stringReplace" },
 683 );
 684
 685 /**
 686  * Returns the result of replacing the string representation of the
 687  * provided value with the provided replacement, using the provided
 688  * matcher and according to the algorithm of `String::replaceAll´.
 689  */
 690 export const stringReplaceAll = createCallableFunction(
 691   stringPrototype.replaceAll,
 692   { name: "stringReplaceAll" },
 693 );
 694
 695 /**
 696  * Returns the result of searching the string representation of the
 697  * provided value using the provided matcher and according to the
 698  * algorithm of `String::search´.
 699  */
 700 export const stringSearch = createCallableFunction(
 701   stringPrototype.search,
 702   { name: "stringSearch" },
 703 );
 704
 705 /**
 706  * Returns a slice of the string representation of the provided value
 707  * according to the algorithm of `String::slice´.
 708  */
 709 export const stringSlice = createCallableFunction(
 710   stringPrototype.slice,
 711   { name: "stringSlice" },
 712 );
 713
 714 /**
 715  * Returns the result of splitting of the string representation of the
 716  * provided value on the provided separator according to the algorithm
 717  * of `String::split´.
 718  */
 719 export const stringSplit = createCallableFunction(
 720   stringPrototype.split,
 721   { name: "stringSplit" },
 722 );
 723
 724 /**
 725  * Returns whether the string representation of the provided value
 726  * starts with the provided search string according to the algorithm of
 727  * `String::startsWith´.
 728  */
 729 export const stringStartsWith = createCallableFunction(
 730   stringPrototype.startsWith,
 731   { name: "stringStartsWith" },
 732 );
 733
 734 /**
 735  * Returns the value of the provided string.
 736  *
 737  * ※ This is effectively an alias for the `String::valueOf´.
 738  *
 739  * ☡ This function throws if the provided argument is not a string and
 740  * does not have a `[[StringData]]´ slot.
 741  */
 742 export const stringValue = createCallableFunction(
 743   stringPrototype.valueOf,
 744   { name: "stringValue" },
 745 );
 746
 747 /**
 748  * Returns the result of stripping leading and trailing Ascii
 749  * whitespace from the provided value and collapsing other Ascii
 750  * whitespace in the string representation of the provided value.
 751  */
 752 export const stripAndCollapseAsciiWhitespace = ($) =>
 753   stripLeadingAndTrailingAsciiWhitespace(
 754     stringReplaceAll(
 755       `${$}`,
 756       /[\n\r\t\f ]+/gu,
 757       " ",
 758     ),
 759   );
 760
 761 /**
 762  * Returns the result of stripping leading and trailing Ascii
 763  * whitespace from the string representation of the provided value.
 764  */
 765 export const stripLeadingAndTrailingAsciiWhitespace = ($) =>
 766   call(reExec, /^[\n\r\t\f ]*([^]*?)[\n\r\t\f ]*$/u, [$])[1];
 767
 768 /**
 769  * Returns a substring of the string representation of the provided
 770  * value according to the algorithm of `String::substring´.
 771  */
 772 export const substring = createCallableFunction(
 773   stringPrototype.substring,
 774 );
 775
 776 /**
 777  * Returns the result of converting the provided value to a string of
 778  * scalar values by replacing (unpaired) surrogate values with
 779  * U+FFFD.
 780  */
 781 export const toScalarValueString = createCallableFunction(
 782   String.prototype.toWellFormed,
 783   { name: "toScalarValueString" },
 784 );
 785
 786 /**
 787  * Returns the result of converting the provided value to a string.
 788  *
 789  * ☡ This method throws for symbols and other objects without a string
 790  * representation.
 791  */
 792 export const toString = ($) => `${$}`;