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

   1 // ♓🌟 Piscēs ∷ collection.js
   2 // ====================================================================
   3 //
   4 // Copyright © 2020–2022 Lady [@ Lady’s Computer].
   5 //
   6 // This Source Code Form is subject to the terms of the Mozilla Public
   7 // License, v. 2.0. If a copy of the MPL was not distributed with this
   8 // file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
   9
  10 import { call, makeCallable } from "./function.js";
  11 import {
  12   floor,
  13   isIntegralNumber,
  14   isNan,
  15   max,
  16   MAXIMUM_SAFE_INTEGRAL_NUMBER,
  17   min,
  18 } from "./numeric.js";
  19 import { sameValue, type } from "./value.js";
  20
  21 export const {
  22   /** Returns an array of the provided values. */
  23   of: array,
  24
  25   /** Returns whether the provided value is an array. */
  26   isArray,
  27
  28   /** Returns an array created from the provided arraylike. */
  29   from: toArray,
  30 } = Array;
  31
  32 /**
  33  * Returns -0 if the provided argument is "-0"; returns a number
  34  * representing the index if the provided argument is a canonical
  35  * numeric index string; otherwise, returns undefined.
  36  *
  37  * There is no clamping of the numeric index, but note that numbers
  38  * above 2^53 − 1 are not safe nor valid integer indices.
  39  */
  40 export const canonicalNumericIndexString = ($) => {
  41   if (typeof $ !== "string") {
  42     return undefined;
  43   } else if ($ === "-0") {
  44     return -0;
  45   } else {
  46     const n = +$;
  47     return $ === `${n}` ? n : undefined;
  48   }
  49 };
  50
  51 /**
  52  * Returns the result of catenating the provided arraylikes, returning
  53  * a new collection according to the algorithm of Array::concat.
  54  */
  55 export const catenate = makeCallable(Array.prototype.concat);
  56
  57 /**
  58  * Copies the items in the provided object to a new location according
  59  * to the algorithm of Array::copyWithin.
  60  */
  61 export const copyWithin = makeCallable(Array.prototype.copyWithin);
  62
  63 /**
  64  * Fills the provided object with the provided value using the
  65  * algorithm of Array::fill.
  66  */
  67 export const fill = makeCallable(Array.prototype.fill);
  68
  69 /**
  70  * Returns the result of filtering the provided object with the
  71  * provided callback, using the algorithm of Array::filter.
  72  */
  73 export const filter = makeCallable(Array.prototype.filter);
  74
  75 /**
  76  * Returns the first index in the provided object whose value satisfies
  77  * the provided callback using the algorithm of Array::findIndex.
  78  */
  79 export const findIndex = makeCallable(Array.prototype.findIndex);
  80
  81 /**
  82  * Returns the first indexed entry in the provided object whose value
  83  * satisfies the provided callback.
  84  *
  85  * If a third argument is supplied, it will be used as the this value
  86  * of the callback.
  87  */
  88 export const findIndexedEntry = (
  89   $,
  90   callback,
  91   thisArg = undefined,
  92 ) => {
  93   let result = undefined;
  94   findItem($, (kValue, k, O) => {
  95     if (call(callback, thisArg, [kValue, k, O])) {
  96       // The callback succeeded.
  97       result = [k, kValue];
  98       return true;
  99     } else {
 100       // The callback failed.
 101       return false;
 102     }
 103   });
 104   return result;
 105 };
 106
 107 /**
 108  * Returns the first indexed value in the provided object which
 109  * satisfies the provided callback, using the algorithm of Array::find.
 110  */
 111 export const findItem = makeCallable(Array.prototype.find);
 112
 113 /**
 114  * Returns the result of flatmapping the provided value with the
 115  * provided callback using the algorithm of Array::flatMap.
 116  */
 117 export const flatmap = makeCallable(Array.prototype.flatMap);
 118
 119 /**
 120  * Returns the result of flattening the provided object using the
 121  * algorithm of Array::flat.
 122  */
 123 export const flatten = makeCallable(Array.prototype.flat);
 124
 125 /**
 126  * Returns the first index of the provided object with a value
 127  * equivalent to the provided value according to the algorithm of
 128  * Array::indexOf.
 129  */
 130 export const getFirstIndex = makeCallable(Array.prototype.indexOf);
 131
 132 /**
 133  * Returns the item on the provided object at the provided index using
 134  * the algorithm of Array::at.
 135  */
 136 export const getItem = makeCallable(Array.prototype.at);
 137
 138 /**
 139  * Returns the last index of the provided object with a value
 140  * equivalent to the provided value according to the algorithm of
 141  * Array::lastIndexOf.
 142  */
 143 export const getLastIndex = makeCallable(Array.prototype.lastIndexOf);
 144
 145 /**
 146  * Returns whether every indexed value in the provided object satisfies
 147  * the provided function, using the algorithm of Array::every.
 148  */
 149 export const hasEvery = makeCallable(Array.prototype.every);
 150
 151 /**
 152  * Returns whether the provided object has an indexed value which
 153  * satisfies the provided function, using the algorithm of Array::some.
 154  */
 155 export const hasSome = makeCallable(Array.prototype.some);
 156
 157 /**
 158  * Returns whether the provided object has an indexed value equivalent
 159  * to the provided value according to the algorithm of Array::includes.
 160  *
 161  * > ☡ This algorithm treats missing values as `undefined` rather than
 162  * > skipping them.
 163  */
 164 export const includes = makeCallable(Array.prototype.includes);
 165
 166 /**
 167  * Returns an iterator over the indexed entries in the provided value
 168  * according to the algorithm of Array::entries.
 169  */
 170 export const indexedEntries = makeCallable(Array.prototype.entries);
 171
 172 /**
 173  * Returns an iterator over the indices in the provided value according
 174  * to the algorithm of Array::keys.
 175  */
 176 export const indices = makeCallable(Array.prototype.keys);
 177
 178 /** Returns whether the provided value is an array index string. */
 179 export const isArrayIndexString = ($) => {
 180   const value = canonicalNumericIndexString($);
 181   if (value !== undefined) {
 182     // The provided value is a canonical numeric index string.
 183     return sameValue(value, 0) || value > 0 && value < -1 >>> 0 &&
 184         value === toLength(value);
 185   } else {
 186     // The provided value is not a canonical numeric index string.
 187     return false;
 188   }
 189 };
 190
 191 /**
 192  * Returns whether the provided object is a collection.
 193  *
 194  * The definition of “collection” used by Piscēs is similar to
 195  * Ecmascript’s definition of an arraylike object, but it differs in
 196  * a few ways :—
 197  *
 198  * - It requires the provided value to be a proper object.
 199  *
 200  * - It requires the `length` property to be an integer index.
 201  *
 202  * - It requires the object to be concat‐spreadable, meaning it must
 203  *   either be an array or have `[Symbol.isConcatSpreadable]` be true.
 204  */
 205 export const isCollection = ($) => {
 206   if (!(type($) === "object" && "length" in $)) {
 207     // The provided value is not an object or does not have a `length`.
 208     return false;
 209   } else {
 210     try {
 211       toIndex($.length); // will throw if `length` is not an index
 212       return isConcatSpreadable($);
 213     } catch {
 214       return false;
 215     }
 216   }
 217 };
 218
 219 /**
 220  * Returns whether the provided value is spreadable during array
 221  * concatenation.
 222  *
 223  * This is also used to determine which things should be treated as
 224  * collections.
 225  */
 226 export const isConcatSpreadable = ($) => {
 227   if (type($) !== "object") {
 228     // The provided value is not an object.
 229     return false;
 230   } else {
 231     // The provided value is an object.
 232     const spreadable = $[Symbol.isConcatSpreadable];
 233     return spreadable !== undefined ? !!spreadable : isArray($);
 234   }
 235 };
 236
 237 /** Returns whether the provided value is an integer index string. */
 238 export const isIntegerIndexString = ($) => {
 239   const value = canonicalNumericIndexString($);
 240   if (value !== undefined && isIntegralNumber(value)) {
 241     // The provided value is a canonical numeric index string.
 242     return sameValue(value, 0) ||
 243       value > 0 && value <= MAXIMUM_SAFE_INTEGRAL_NUMBER &&
 244         value === toLength(value);
 245   } else {
 246     // The provided value is not a canonical numeric index string.
 247     return false;
 248   }
 249 };
 250
 251 /**
 252  * Returns an iterator over the items in the provided value according
 253  * to the algorithm of Array::values.
 254  */
 255 export const items = makeCallable(Array.prototype.values);
 256
 257 /**
 258  * Returns the length of the provided arraylike object.
 259  *
 260  * Will throw if the provided object is not arraylike.
 261  *
 262  * This can produce larger lengths than can actually be stored in
 263  * arrays, because no such restrictions exist on arraylike methods.
 264  */
 265 export const lengthOfArrayLike = ({ length }) => toLength(length);
 266
 267 /**
 268  * Returns the result of mapping the provided value with the provided
 269  * callback using the algorithm of Array::map.
 270  */
 271 export const map = makeCallable(Array.prototype.map);
 272
 273 /** Pops from the provided value using the algorithm of Array::pop. */
 274 export const pop = makeCallable(Array.prototype.pop);
 275
 276 /**
 277  * Pushes onto the provided value using the algorithm of Array::push.
 278  */
 279 export const push = makeCallable(Array.prototype.push);
 280
 281 /**
 282  * Returns the result of reducing the provided value with the provided
 283  * callback, using the algorithm of Array::reduce.
 284  */
 285 export const reduce = makeCallable(Array.prototype.reduce);
 286
 287 /**
 288  * Reverses the provided value using the algorithm of Array::reverse.
 289  */
 290 export const reverse = makeCallable(Array.prototype.reverse);
 291
 292 /** Shifts the provided value using the algorithm of Array::shift. */
 293 export const shift = makeCallable(Array.prototype.shift);
 294
 295 /**
 296  * Returns a slice of the provided value using the algorithm of
 297  * Array::slice.
 298  */
 299 export const slice = makeCallable(Array.prototype.slice);
 300
 301 /**
 302  * Sorts the provided value in‐place using the algorithm of
 303  * Array::sort.
 304  */
 305 export const sort = makeCallable(Array.prototype.sort);
 306
 307 /**
 308  * Splices into and out of the provided value using the algorithm of
 309  * Array::splice.
 310  */
 311 export const splice = makeCallable(Array.prototype.splice);
 312
 313 /**
 314  * Returns the result of converting the provided value to an array
 315  * index, or throws an error if it is out of range.
 316  */
 317 export const toIndex = ($) => {
 318   const integer = floor($);
 319   if (isNan(integer) || integer == 0) {
 320     // The value is zero·like.
 321     return 0;
 322   } else {
 323     // The value is not zero·like.
 324     const clamped = toLength(integer);
 325     if (clamped !== integer) {
 326       // Clamping the value changes it.
 327       throw new RangeError(`Piscēs: Index out of range: ${$}.`);
 328     } else {
 329       // The value is within appropriate bounds.
 330       return integer;
 331     }
 332   }
 333 };
 334
 335 /** Returns the result of converting the provided value to a length. */
 336 export const toLength = ($) => {
 337   const len = floor($);
 338   return isNan(len) || len == 0
 339     ? 0
 340     : max(min(len, MAXIMUM_SAFE_INTEGRAL_NUMBER), 0);
 341 };
 342
 343 /**
 344  * Unshifts the provided value using the algorithm of Array::unshift.
 345  */
 346 export const unshift = makeCallable(Array.prototype.unshift);