// ♓🌟 Piscēs ∷ string.js
// ====================================================================
//
-// Copyright © 2022 Lady [@ Lady’s Computer].
+// Copyright © 2022–2023 Lady [@ Lady’s Computer].
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
+import {
+ bind,
+ call,
+ createArrowFunction,
+ createCallableFunction,
+ identity,
+} from "./function.js";
+import {
+ arrayIteratorFunction,
+ stringIteratorFunction,
+} from "./iterable.js";
+import {
+ defineOwnDataProperty,
+ defineOwnProperties,
+ getOwnPropertyDescriptors,
+ objectCreate,
+ setPropertyValues,
+ setPrototype,
+} from "./object.js";
+import { sameValue, toLength, UNDEFINED } from "./value.js";
+
+const RE = RegExp;
+const { prototype: rePrototype } = RE;
+const { prototype: arrayPrototype } = Array;
+const { prototype: stringPrototype } = String;
+
+const { exec: reExec } = rePrototype;
+
+export const {
+ /**
+ * A `RegExp`like object which only matches entire strings, and may
+ * have additional constraints specified.
+ *
+ * Matchers are callable objects and will return true if they are
+ * called with a string that they match, and false otherwise.
+ * Matchers will always return false if called with nonstrings,
+ * although other methods like `::exec` coerce their arguments and
+ * may still return true.
+ */
+ Matcher,
+} = (() => {
+ const { toString: reToString } = rePrototype;
+ const getDotAll =
+ Object.getOwnPropertyDescriptor(rePrototype, "dotAll").get;
+ const getFlags =
+ Object.getOwnPropertyDescriptor(rePrototype, "flags").get;
+ const getGlobal =
+ Object.getOwnPropertyDescriptor(rePrototype, "global").get;
+ const getHasIndices =
+ Object.getOwnPropertyDescriptor(rePrototype, "hasIndices").get;
+ const getIgnoreCase =
+ Object.getOwnPropertyDescriptor(rePrototype, "ignoreCase").get;
+ const getMultiline =
+ Object.getOwnPropertyDescriptor(rePrototype, "multiline").get;
+ const getSource =
+ Object.getOwnPropertyDescriptor(rePrototype, "source").get;
+ const getSticky =
+ Object.getOwnPropertyDescriptor(rePrototype, "sticky").get;
+ const getUnicode =
+ Object.getOwnPropertyDescriptor(rePrototype, "unicode").get;
+
+ const Matcher = class extends identity {
+ #constraint;
+ #regExp;
+
+ /**
+ * Constructs a new `Matcher` from the provided source.
+ *
+ * If the provided source is a regular expression, then it must
+ * have the unicode flag set. Otherwise, it is interpreted as the
+ * string source of a regular expression with the unicode flag set.
+ *
+ * Other flags are taken from the provided regular expression
+ * object, if any are present.
+ *
+ * A name for the matcher may be provided as the second argument.
+ *
+ * A callable constraint on acceptable inputs may be provided as a
+ * third argument. If provided, it will be called with three
+ * arguments whenever a match appears successful: first, the string
+ * being matched, second, the match result, and third, the
+ * `Matcher` object itself. If the return value of this call is
+ * falsey, then the match will be considered a failure.
+ *
+ * ☡ If the provided source regular expression uses nongreedy
+ * quantifiers, it may not match the whole string even if a match
+ * with the whole string is possible. Surround the regular
+ * expression with `^(?:` and `)$` if you don’t want nongreedy
+ * regular expressions to fail when shorter matches are possible.
+ */
+ constructor(source, name = UNDEFINED, constraint = null) {
+ super(
+ ($) => {
+ if (typeof $ !== "string") {
+ // The provided value is not a string.
+ return false;
+ } else {
+ // The provided value is a string. Set the `.lastIndex` of
+ // the regular expression to 0 and see if the first attempt
+ // at a match matches the whole string and passes the
+ // provided constraint (if present).
+ regExp.lastIndex = 0;
+ const result = call(reExec, regExp, [$]);
+ return result?.[0] === $ &&
+ (constraint === null || constraint($, result, this));
+ }
+ },
+ );
+ const regExp = this.#regExp = (() => {
+ try {
+ call(reExec, source, [""]); // throws if source not a RegExp
+ } catch {
+ return new RE(`${source}`, "u");
+ }
+ const unicode = call(getUnicode, source, []);
+ if (!unicode) {
+ // The provided regular expression does not have a unicode
+ // flag.
+ throw new TypeError(
+ `Piscēs: Cannot create Matcher from non‐Unicode RegExp: ${source}`,
+ );
+ } else {
+ // The provided regular expression has a unicode flag.
+ return new RE(source);
+ }
+ })();
+ if (constraint !== null && typeof constraint !== "function") {
+ throw new TypeError(
+ "Piscēs: Cannot construct Matcher: Constraint is not callable.",
+ );
+ } else {
+ this.#constraint = constraint;
+ return defineOwnProperties(
+ setPrototype(this, matcherPrototype),
+ {
+ lastIndex: setPropertyValues(objectCreate(null), {
+ configurable: false,
+ enumerable: false,
+ value: 0,
+ writable: false,
+ }),
+ name: defineOwnDataProperty(
+ objectCreate(null),
+ "value",
+ name != null
+ ? `${name}`
+ : `Matcher(${call(reToString, regExp, [])})`,
+ ),
+ },
+ );
+ }
+ }
+
+ /** Gets whether the dot‐all flag is present on this `Matcher`. */
+ get dotAll() {
+ return call(getDotAll, this.#regExp, []);
+ }
+
+ /**
+ * Executes this `Matcher` on the provided value and returns the
+ * result if there is a match, or null otherwise.
+ *
+ * Matchers only match if they can match the entire value on the
+ * first attempt.
+ *
+ * ☡ The match result returned by this method will be the same as
+ * that passed to the constraint function—and may have been
+ * modified by said function prior to being returned.
+ */
+ exec($) {
+ const regExp = this.#regExp;
+ const constraint = this.#constraint;
+ const string = `${$}`;
+ regExp.lastIndex = 0;
+ const result = call(reExec, regExp, [string]);
+ if (
+ result?.[0] === string &&
+ (constraint === null || constraint(string, result, this))
+ ) {
+ // The entire string was matched and the constraint, if
+ // present, returned a truthy value.
+ return result;
+ } else {
+ // The entire string was not matched or the constraint returned
+ // a falsey value.
+ return null;
+ }
+ }
+
+ /**
+ * Gets the flags present on this `Matcher`.
+ *
+ * ※ This needs to be defined because the internal `RegExp` object
+ * may have flags which are not yet recognized by ♓🌟 Piscēs.
+ */
+ get flags() {
+ return call(getFlags, this.#regExp, []);
+ }
+
+ /** Gets whether the global flag is present on this `Matcher`. */
+ get global() {
+ return call(getGlobal, this.#regExp, []);
+ }
+
+ /**
+ * Gets whether the has‐indices flag is present on this `Matcher`.
+ */
+ get hasIndices() {
+ return call(getHasIndices, this.#regExp, []);
+ }
+
+ /**
+ * Gets whether the ignore‐case flag is present on this `Matcher`.
+ */
+ get ignoreCase() {
+ return call(getIgnoreCase, this.#regExp, []);
+ }
+
+ /**
+ * Gets whether the multiline flag is present on this `Matcher`.
+ */
+ get multiline() {
+ return call(getMultiline, this.#regExp, []);
+ }
+
+ /** Gets the regular expression source for this `Matcher`. */
+ get source() {
+ return call(getSource, this.#regExp, []);
+ }
+
+ /** Gets whether the sticky flag is present on this `Matcher`. */
+ get sticky() {
+ return call(getSticky, this.#regExp, []);
+ }
+
+ /**
+ * Gets whether the unicode flag is present on this `Matcher`.
+ *
+ * ※ This will always be true.
+ */
+ get unicode() {
+ return call(getUnicode, this.#regExp, []);
+ }
+ };
+
+ const matcherConstructor = Object.defineProperties(
+ class extends RegExp {
+ constructor(...args) {
+ return new Matcher(...args);
+ }
+ },
+ {
+ name: defineOwnDataProperty(
+ Object.create(null),
+ "value",
+ "Matcher",
+ ),
+ length: defineOwnDataProperty(Object.create(null), "value", 1),
+ },
+ );
+ const matcherPrototype = defineOwnProperties(
+ matcherConstructor.prototype,
+ getOwnPropertyDescriptors(Matcher.prototype),
+ {
+ constructor: defineOwnDataProperty(
+ Object.create(null),
+ "value",
+ matcherConstructor,
+ ),
+ },
+ );
+
+ return { Matcher: matcherConstructor };
+})();
+
+export const {
+ /**
+ * Returns the result of converting the provided value to A·S·C·I·I
+ * lowercase.
+ */
+ asciiLowercase,
+
+ /**
+ * Returns the result of converting the provided value to A·S·C·I·I
+ * uppercase.
+ */
+ asciiUppercase,
+} = (() => {
+ const {
+ toLowerCase: stringToLowercase,
+ toUpperCase: stringToUppercase,
+ } = stringPrototype;
+ return {
+ asciiLowercase: ($) =>
+ stringReplaceAll(
+ `${$}`,
+ /[A-Z]/gu,
+ createCallableFunction(stringToLowercase),
+ ),
+ asciiUppercase: ($) =>
+ stringReplaceAll(
+ `${$}`,
+ /[a-z]/gu,
+ createCallableFunction(stringToUppercase),
+ ),
+ };
+})();
+
/**
- * Returns the result of converting the provided value to A·S·C·I·I
- * lowercase.
+ * Returns −0 if the provided argument is "-0"; returns a number
+ * representing the index if the provided argument is a canonical
+ * numeric index string; otherwise, returns undefined.
+ *
+ * There is no clamping of the numeric index, but note that numbers
+ * above 2^53 − 1 are not safe nor valid integer indices.
*/
-export const asciiLowercase = ($) =>
- `${$}`.replaceAll(
- /[A-Z]/gu,
- Function.prototype.call.bind(String.prototype.toLowerCase),
+export const canonicalNumericIndexString = ($) => {
+ if (typeof $ !== "string") {
+ return UNDEFINED;
+ } else if ($ === "-0") {
+ return -0;
+ } else {
+ const n = +$;
+ return $ === `${n}` ? n : UNDEFINED;
+ }
+};
+
+export const {
+ /**
+ * Returns an iterator over the codepoints in the string representation
+ * of the provided value according to the algorithm of
+ * `String::[Symbol.iterator]`.
+ */
+ characters,
+
+ /**
+ * Returns an iterator over the code units in the string
+ * representation of the provided value.
+ */
+ codeUnits,
+
+ /**
+ * Returns an iterator over the codepoints in the string
+ * representation of the provided value.
+ */
+ codepoints,
+
+ /**
+ * Returns an iterator over the scalar values in the string
+ * representation of the provided value.
+ *
+ * Codepoints which are not valid Unicode scalar values are replaced
+ * with U+FFFD.
+ */
+ scalarValues,
+} = (() => {
+ const generateCharacters = function* (character) {
+ yield character;
+ };
+ const generateCodeUnits = function* (ucsCharacter) {
+ yield getCodeUnit(ucsCharacter, 0);
+ };
+ const generateCodepoints = function* (character) {
+ const { allowSurrogates } = this;
+ const codepoint = getCodepoint(character, 0);
+ yield allowSurrogates || codepoint <= 0xD7FF || codepoint >= 0xE000
+ ? codepoint
+ : 0xFFFD;
+ };
+
+ const charactersIterator = stringIteratorFunction(
+ generateCharacters,
+ "String Character Iterator",
);
+ const codeUnitsIterator = arrayIteratorFunction(
+ generateCodeUnits,
+ "String Code Unit Iterator",
+ );
+ const codepointsIterator = stringIteratorFunction(
+ bind(generateCodepoints, { allowSurrogates: true }, []),
+ "String Codepoint Iterator",
+ );
+ const scalarValuesIterator = stringIteratorFunction(
+ bind(generateCodepoints, { allowSurrogates: false }, []),
+ "String Scalar Value Iterator",
+ );
+
+ return {
+ characters: ($) => charactersIterator(`${$}`),
+ codeUnits: ($) => codeUnitsIterator(`${$}`),
+ codepoints: ($) => codepointsIterator(`${$}`),
+ scalarValues: ($) => scalarValuesIterator(`${$}`),
+ };
+})();
/**
- * Returns the result of converting the provided value to A·S·C·I·I
- * uppercase.
+ * Returns the character at the provided position in the string
+ * representation of the provided value according to the algorithm of
+ * `String::codePointAt`.
*/
-export const asciiUppercase = ($) =>
- `${$}`.replaceAll(
- /[a-z]/gu,
- Function.prototype.call.bind(String.prototype.toUpperCase),
- );
+export const getCharacter = ($, pos) => {
+ const codepoint = getCodepoint($, pos);
+ return codepoint == null
+ ? UNDEFINED
+ : stringFromCodepoints(codepoint);
+};
+
+export const {
+ /**
+ * Returns the code unit at the provided position in the string
+ * representation of the provided value according to the algorithm of
+ * `String::charAt`, except that out‐of‐bounds values return undefined
+ * in place of nan.
+ */
+ getCodeUnit,
+
+ /**
+ * Returns a string created from the provided code units.
+ *
+ * ※ This is effectively an alias for `String.fromCharCode`, but
+ * with the same error behaviour as `String.fromCodePoint`.
+ *
+ * ☡ This function throws an error if provided with an argument which
+ * is not an integral number from 0 to FFFF₁₆ inclusive.
+ */
+ stringFromCodeUnits,
+
+ /**
+ * Returns the result of catenating the string representations of the
+ * provided values, returning a new string according to the algorithm
+ * of `String::concat`.
+ *
+ * ※ If no arguments are given, this function returns the empty
+ * string. This is different behaviour than if an explicit undefined
+ * first argument is given, in which case the resulting string will
+ * begin with `"undefined"`.
+ */
+ stringCatenate,
+} = (() => {
+ const { fromCharCode } = String;
+ const { charCodeAt, concat } = String.prototype;
+ const {
+ isInteger: isIntegralNumber,
+ isNaN: isNan,
+ } = Number;
+
+ return {
+ getCodeUnit: ($, n) => {
+ const codeUnit = call(charCodeAt, $, [n]);
+ return isNan(codeUnit) ? UNDEFINED : codeUnit;
+ },
+ stringCatenate: Object.defineProperties(
+ (...args) => call(concat, "", args),
+ { name: { value: "stringCatenate" }, length: { value: 2 } },
+ ),
+ stringFromCodeUnits: Object.defineProperties(
+ (...codeUnits) => {
+ for (let index = 0; index < codeUnits.length; ++index) {
+ // Iterate over each provided code unit and throw if it is
+ // out of range.
+ const nextCU = +codeUnits[index];
+ if (
+ !isIntegralNumber(nextCU) || nextCU < 0 || nextCU > 0xFFFF
+ ) {
+ // The code unit is not an integral number between 0 and
+ // 0xFFFF.
+ throw new RangeError(
+ `Piscēs: Code unit out of range: ${nextCU}.`,
+ );
+ } else {
+ // The code unit is acceptable.
+ /* do nothing */
+ }
+ }
+ return call(fromCharCode, UNDEFINED, codeUnits);
+ },
+ { name: { value: "stringFromCodeUnits" }, length: { value: 1 } },
+ ),
+ };
+})();
/**
- * Returns the result of converting the provided value to a string of
- * scalar values by replacing (unpaired) surrogate values with U+FFFD.
- */
-export const scalarValueString = ($) =>
- String.fromCodePoint(
- ...function* () {
- for (const char of `${$}`) {
- const scalar = char.codePointAt(0);
- yield scalar >= 0xD800 && scalar <= 0xDFFF ? 0xFFFD : scalar;
- }
- }(),
- );
+ * Returns the codepoint at the provided position in the string
+ * representation of the provided value according to the algorithm of
+ * `String::codePointAt`.
+ */
+export const getCodepoint = createCallableFunction(
+ stringPrototype.codePointAt,
+ { name: "getCodepoint" },
+);
+
+/**
+ * Returns the index of the first occurrence of the search string in
+ * the string representation of the provided value according to the
+ * algorithm of `String::indexOf`.
+ */
+export const getFirstSubstringIndex = createCallableFunction(
+ stringPrototype.indexOf,
+ { name: "getFirstSubstringIndex" },
+);
+
+/**
+ * Returns the index of the last occurrence of the search string in the
+ * string representation of the provided value according to the
+ * algorithm of `String::lastIndexOf`.
+ */
+export const getLastSubstringIndex = createCallableFunction(
+ stringPrototype.lastIndexOf,
+ { name: "getLastSubstringIndex" },
+);
+
+/** Returns whether the provided value is an array index. */
+export const isArrayIndexString = ($) => {
+ const value = canonicalNumericIndexString($);
+ if (value !== UNDEFINED) {
+ // The provided value is a canonical numeric index string; return
+ // whether it is in range for array indices.
+ return sameValue(value, 0) ||
+ value === toLength(value) && value > 0 && value < -1 >>> 0;
+ } else {
+ // The provided value is not a canonical numeric index string.
+ return false;
+ }
+};
+
+/** Returns whether the provided value is an integer index string. */
+export const isIntegerIndexString = ($) => {
+ const value = canonicalNumericIndexString($);
+ if (value !== UNDEFINED) {
+ // The provided value is a canonical numeric index string; return
+ // whether it is in range for integer indices.
+ return sameValue(value, 0) ||
+ value === toLength(value) && value > 0;
+ } else {
+ // The provided value is not a canonical numeric index string.
+ return false;
+ }
+};
+
+/**
+ * Returns the result of joining the provided iterable.
+ *
+ * If no separator is provided, it defaults to ",".
+ *
+ * If a value is nullish, it will be stringified as the empty string.
+ */
+export const join = (() => {
+ const { join: arrayJoin } = arrayPrototype;
+ const join = ($, separator) =>
+ call(
+ arrayJoin,
+ [...$],
+ [separator === UNDEFINED ? "," : `${separator}`],
+ );
+ return join;
+})();
+
+/**
+ * Returns a string created from the raw value of the tagged template
+ * literal.
+ *
+ * ※ This is effectively an alias for `String.raw`.
+ */
+export const rawString = createArrowFunction(String.raw, {
+ name: "rawString",
+});
/**
- * Returns the result of splitting the provided value on A·S·C·I·I
+ * Returns a string created from the provided codepoints.
+ *
+ * ※ This is effectively an alias for `String.fromCodePoint`.
+ *
+ * ☡ This function throws an error if provided with an argument which
+ * is not an integral number from 0 to 10FFFF₁₆ inclusive.
+ */
+export const stringFromCodepoints = createArrowFunction(
+ String.fromCodePoint,
+ { name: "stringFromCodepoints" },
+);
+
+/**
+ * Returns the result of splitting the provided value on Ascii
* whitespace.
*/
-export const splitOnASCIIWhitespace = ($) =>
- stripAndCollapseASCIIWhitespace($).split(" ");
+export const splitOnAsciiWhitespace = ($) =>
+ stringSplit(stripAndCollapseAsciiWhitespace($), " ");
/**
* Returns the result of splitting the provided value on commas,
- * trimming A·S·C·I·I whitespace from the resulting tokens.
+ * trimming Ascii whitespace from the resulting tokens.
*/
export const splitOnCommas = ($) =>
- stripLeadingAndTrailingASCIIWhitespace(
- `${$}`.replaceAll(
- /[\n\r\t\f ]*,[\n\r\t\f ]*/gu,
- ",",
+ stringSplit(
+ stripLeadingAndTrailingAsciiWhitespace(
+ stringReplaceAll(
+ `${$}`,
+ /[\n\r\t\f ]*,[\n\r\t\f ]*/gu,
+ ",",
+ ),
),
- ).split(",");
+ ",",
+ );
+
+/**
+ * Returns whether the string representation of the provided value ends
+ * with the provided search string according to the algorithm of
+ * `String::endsWith`.
+ */
+export const stringEndsWith = createCallableFunction(
+ stringPrototype.endsWith,
+ { name: "stringEndsWith" },
+);
+
+/**
+ * Returns whether the string representation of the provided value
+ * contains the provided search string according to the algorithm of
+ * `String::includes`.
+ */
+export const stringIncludes = createCallableFunction(
+ stringPrototype.includes,
+ { name: "stringIncludes" },
+);
+
+/**
+ * Returns the result of matching the string representation of the
+ * provided value with the provided matcher according to the algorithm
+ * of `String::match`.
+ */
+export const stringMatch = createCallableFunction(
+ stringPrototype.match,
+ { name: "stringMatch" },
+);
+
+/**
+ * Returns the result of matching the string representation of the
+ * provided value with the provided matcher according to the algorithm
+ * of `String::matchAll`.
+ */
+export const stringMatchAll = createCallableFunction(
+ stringPrototype.matchAll,
+ { name: "stringMatchAll" },
+);
+
+/**
+ * Returns the normalized form of the string representation of the
+ * provided value according to the algorithm of `String::normalize`.
+ */
+export const stringNormalize = createCallableFunction(
+ stringPrototype.normalize,
+ { name: "stringNormalize" },
+);
/**
- * Returns the result of stripping leading and trailing A·S·C·I·I
- * whitespace from the provided value.
+ * Returns the result of padding the end of the string representation
+ * of the provided value padded until it is the desired length
+ * according to the algorithm of `String::padEnd`.
*/
-export const stripLeadingAndTrailingASCIIWhitespace = ($) =>
- /^[\n\r\t\f ]*([^]*?)[\n\r\t\f ]*$/u.exec($)[1];
+export const stringPadEnd = createCallableFunction(
+ stringPrototype.padEnd,
+ { name: "stringPadEnd" },
+);
/**
- * Returns the result of stripping leading and trailing A·S·C·I·I
- * whitespace from the provided value and collapsing other A·S·C·I·I
- * whitespace in the provided value.
+ * Returns the result of padding the start of the string representation
+ * of the provided value padded until it is the desired length
+ * according to the algorithm of `String::padStart`.
*/
-export const stripAndCollapseASCIIWhitespace = ($) =>
- stripLeadingAndTrailingASCIIWhitespace(
- `${$}`.replaceAll(
+export const stringPadStart = createCallableFunction(
+ stringPrototype.padStart,
+ { name: "stringPadStart" },
+);
+
+/**
+ * Returns the result of repeating the string representation of the
+ * provided value the provided number of times according to the
+ * algorithm of `String::repeat`.
+ */
+export const stringRepeat = createCallableFunction(
+ stringPrototype.repeat,
+ { name: "stringRepeat" },
+);
+
+/**
+ * Returns the result of replacing the string representation of the
+ * provided value with the provided replacement, using the provided
+ * matcher and according to the algorithm of `String::replace`.
+ */
+export const stringReplace = createCallableFunction(
+ stringPrototype.replace,
+ { name: "stringReplace" },
+);
+
+/**
+ * Returns the result of replacing the string representation of the
+ * provided value with the provided replacement, using the provided
+ * matcher and according to the algorithm of `String::replaceAll`.
+ */
+export const stringReplaceAll = createCallableFunction(
+ stringPrototype.replaceAll,
+ { name: "stringReplaceAll" },
+);
+
+/**
+ * Returns the result of searching the string representation of the
+ * provided value using the provided matcher and according to the
+ * algorithm of `String::search`.
+ */
+export const stringSearch = createCallableFunction(
+ stringPrototype.search,
+ { name: "stringSearch" },
+);
+
+/**
+ * Returns a slice of the string representation of the provided value
+ * according to the algorithm of `String::slice`.
+ */
+export const stringSlice = createCallableFunction(
+ stringPrototype.slice,
+ { name: "stringSlice" },
+);
+
+/**
+ * Returns the result of splitting of the string representation of the
+ * provided value on the provided separator according to the algorithm
+ * of `String::split`.
+ */
+export const stringSplit = createCallableFunction(
+ stringPrototype.split,
+ { name: "stringSplit" },
+);
+
+/**
+ * Returns whether the string representation of the provided value
+ * starts with the provided search string according to the algorithm of
+ * `String::startsWith`.
+ */
+export const stringStartsWith = createCallableFunction(
+ stringPrototype.startsWith,
+ { name: "stringStartsWith" },
+);
+
+/**
+ * Returns the value of the provided string.
+ *
+ * ※ This is effectively an alias for the `String::valueOf`.
+ *
+ * ☡ This function throws if the provided argument is not a string and
+ * does not have a `[[StringData]]` slot.
+ */
+export const stringValue = createCallableFunction(
+ stringPrototype.valueOf,
+ { name: "stringValue" },
+);
+
+/**
+ * Returns the result of stripping leading and trailing Ascii
+ * whitespace from the provided value and collapsing other Ascii
+ * whitespace in the string representation of the provided value.
+ */
+export const stripAndCollapseAsciiWhitespace = ($) =>
+ stripLeadingAndTrailingAsciiWhitespace(
+ stringReplaceAll(
+ `${$}`,
/[\n\r\t\f ]+/gu,
" ",
),
);
+
+/**
+ * Returns the result of stripping leading and trailing Ascii
+ * whitespace from the string representation of the provided value.
+ */
+export const stripLeadingAndTrailingAsciiWhitespace = ($) =>
+ call(reExec, /^[\n\r\t\f ]*([^]*?)[\n\r\t\f ]*$/u, [$])[1];
+
+/**
+ * Returns a substring of the string representation of the provided
+ * value according to the algorithm of `String::substring`.
+ */
+export const substring = createCallableFunction(
+ stringPrototype.substring,
+);
+
+/**
+ * Returns the result of converting the provided value to a string of
+ * scalar values by replacing (unpaired) surrogate values with
+ * U+FFFD.
+ */
+export const toScalarValueString = createCallableFunction(
+ String.prototype.toWellFormed,
+ { name: "toScalarValueString" },
+);
+
+/**
+ * Returns the result of converting the provided value to a string.
+ *
+ * ☡ This method throws for symbols and other objects without a string
+ * representation.
+ */
+export const toString = ($) => `${$}`;
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