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

   1 // ♓🌟 Piscēs ∷ collection.js
   2 // ====================================================================
   3 //
   4 // Copyright © 2020–2023 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, createCallableFunction } from "./function.js";
  11 import {
  12   canonicalNumericIndexString,
  13   lengthOfArraylike,
  14   sameValue,
  15   toIndex,
  16   toLength,
  17   type,
  18 } from "./value.js";
  19
  20 const { prototype: arrayPrototype } = Array;
  21
  22 export const {
  23   /** Returns an array of the provided values. */
  24   of: array,
  25
  26   /** Returns whether the provided value is an array. */
  27   isArray,
  28
  29   /** Returns an array created from the provided arraylike. */
  30   from: toArray,
  31 } = Array;
  32
  33 /**
  34  * Returns the result of catenating the provided arraylikes into a new
  35  * collection according to the algorithm of `Array::concat`.
  36  */
  37 export const catenate = createCallableFunction(
  38   arrayPrototype.concat,
  39   "catenate",
  40 );
  41
  42 /**
  43  * Copies the items in the provided object to a new location according
  44  * to the algorithm of `Array::copyWithin`.
  45  */
  46 export const copyWithin = createCallableFunction(
  47   arrayPrototype.copyWithin,
  48 );
  49
  50 /**
  51  * Fills the provided object with the provided value according to the
  52  * algorithm of `Array::fill`.
  53  */
  54 export const fill = createCallableFunction(arrayPrototype.fill);
  55
  56 /**
  57  * Returns the result of filtering the provided object with the
  58  * provided callback, according to the algorithm of `Array::filter`.
  59  */
  60 export const filter = createCallableFunction(arrayPrototype.filter);
  61
  62 /**
  63  * Returns the first index in the provided object whose value satisfies
  64  * the provided callback according to the algorithm of
  65  * `Array::findIndex`.
  66  */
  67 export const findIndex = createCallableFunction(
  68   arrayPrototype.findIndex,
  69 );
  70
  71 /**
  72  * Returns the first indexed entry in the provided object whose value
  73  * satisfies the provided callback.
  74  *
  75  * If a third argument is supplied, it will be used as the this value
  76  * of the callback.
  77  */
  78 export const findIndexedEntry = (
  79   $,
  80   callback,
  81   thisArg = undefined,
  82 ) => {
  83   let result = undefined;
  84   findItem($, (kValue, k, O) => {
  85     if (call(callback, thisArg, [kValue, k, O])) {
  86       // The callback succeeded.
  87       result = [k, kValue];
  88       return true;
  89     } else {
  90       // The callback failed.
  91       return false;
  92     }
  93   });
  94   return result;
  95 };
  96
  97 /**
  98  * Returns the first indexed value in the provided object which
  99  * satisfies the provided callback, according to the algorithm of
 100  * `Array::find`.
 101  */
 102 export const findItem = createCallableFunction(
 103   arrayPrototype.find,
 104   "findItem",
 105 );
 106
 107 /**
 108  * Returns the result of flatmapping the provided value with the
 109  * provided callback according to the algorithm of `Array::flatMap`.
 110  */
 111 export const flatmap = createCallableFunction(
 112   arrayPrototype.flatMap,
 113   "flatmap",
 114 );
 115
 116 /**
 117  * Returns the result of flattening the provided object according to
 118  * the algorithm of `Array::flat`.
 119  */
 120 export const flatten = createCallableFunction(
 121   arrayPrototype.flat,
 122   "flatten",
 123 );
 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 = createCallableFunction(
 131   arrayPrototype.indexOf,
 132   "getFirstIndex",
 133 );
 134
 135 /**
 136  * Returns the item on the provided object at the provided index
 137  * according to the algorithm of `Array::at`.
 138  */
 139 export const getItem = createCallableFunction(
 140   arrayPrototype.at,
 141   "getItem",
 142 );
 143
 144 /**
 145  * Returns the last index of the provided object with a value
 146  * equivalent to the provided value according to the algorithm of
 147  * `Array::lastIndexOf`.
 148  */
 149 export const getLastIndex = createCallableFunction(
 150   arrayPrototype.lastIndexOf,
 151   "getLastIndex",
 152 );
 153
 154 /**
 155  * Returns whether every indexed value in the provided object satisfies
 156  * the provided function, according to the algorithm of `Array::every`.
 157  */
 158 export const hasEvery = createCallableFunction(
 159   arrayPrototype.every,
 160   "hasEvery",
 161 );
 162
 163 /**
 164  * Returns whether the provided object has an indexed value which
 165  * satisfies the provided function, according to the algorithm of
 166  * `Array::some`.
 167  */
 168 export const hasSome = createCallableFunction(
 169   arrayPrototype.some,
 170   "hasSome",
 171 );
 172
 173 /**
 174  * Returns whether the provided object has an indexed value equivalent
 175  * to the provided value according to the algorithm of
 176  * `Array::includes`.
 177  *
 178  * ※ This algorithm treats missing values as `undefined` rather than
 179  * skipping them.
 180  */
 181 export const includes = createCallableFunction(
 182   arrayPrototype.includes,
 183 );
 184
 185 /**
 186  * Returns an iterator over the indexed entries in the provided value
 187  * according to the algorithm of `Array::entries`.
 188  */
 189 export const indexedEntries = createCallableFunction(
 190   arrayPrototype.entries,
 191   "indexedEntries",
 192 );
 193
 194 /**
 195  * Returns an iterator over the indices in the provided value according
 196  * to the algorithm of `Array::keys`.
 197  */
 198 export const indices = createCallableFunction(
 199   arrayPrototype.keys,
 200   "indices",
 201 );
 202
 203 /** Returns whether the provided value is an array index string. */
 204 export const isArrayIndexString = ($) => {
 205   const value = canonicalNumericIndexString($);
 206   if (value !== undefined) {
 207     // The provided value is a canonical numeric index string.
 208     return sameValue(value, 0) || value > 0 && value < -1 >>> 0 &&
 209         value === toLength(value);
 210   } else {
 211     // The provided value is not a canonical numeric index string.
 212     return false;
 213   }
 214 };
 215
 216 /** Returns whether the provided value is arraylike. */
 217 export const isArraylikeObject = ($) => {
 218   if (type($) !== "object") {
 219     return false;
 220   } else {
 221     try {
 222       lengthOfArraylike($); // throws if not arraylike
 223       return true;
 224     } catch {
 225       return false;
 226     }
 227   }
 228 };
 229
 230 /**
 231  * Returns whether the provided object is a collection.
 232  *
 233  * The definition of “collection” used by Piscēs is similar to
 234  * Ecmascript’s definition of an arraylike object, but it differs in
 235  * a few ways :—
 236  *
 237  * - It requires the provided value to be a proper object.
 238  *
 239  * - It requires the `length` property to be an integer index.
 240  *
 241  * - It requires the object to be concat‐spreadable, meaning it must
 242  *   either be an array or have `.[Symbol.isConcatSpreadable]` be true.
 243  */
 244 export const isCollection = ($) => {
 245   if (!(type($) === "object" && "length" in $)) {
 246     // The provided value is not an object or does not have a `length`.
 247     return false;
 248   } else {
 249     try {
 250       toIndex($.length); // will throw if `length` is not an index
 251       return isConcatSpreadable($);
 252     } catch {
 253       return false;
 254     }
 255   }
 256 };
 257
 258 /**
 259  * Returns whether the provided value is spreadable during array
 260  * concatenation.
 261  *
 262  * This is also used to determine which things should be treated as
 263  * collections.
 264  */
 265 export const isConcatSpreadable = ($) => {
 266   if (type($) !== "object") {
 267     // The provided value is not an object.
 268     return false;
 269   } else {
 270     // The provided value is an object.
 271     const spreadable = $[Symbol.isConcatSpreadable];
 272     return spreadable !== undefined ? !!spreadable : isArray($);
 273   }
 274 };
 275
 276 /**
 277  * Returns an iterator over the items in the provided value according
 278  * to the algorithm of `Array::values`.
 279  */
 280 export const items = createCallableFunction(
 281   arrayPrototype.values,
 282   "items",
 283 );
 284
 285 /**
 286  * Returns the result of mapping the provided value with the provided
 287  * callback according to the algorithm of `Array::map`.
 288  */
 289 export const map = createCallableFunction(arrayPrototype.map);
 290
 291 /**
 292  * Pops from the provided value according to the algorithm of
 293  * `Array::pop`.
 294  */
 295 export const pop = createCallableFunction(arrayPrototype.pop);
 296
 297 /**
 298  * Pushes onto the provided value according to the algorithm of
 299  * `Array::push`.
 300  */
 301 export const push = createCallableFunction(arrayPrototype.push);
 302
 303 /**
 304  * Returns the result of reducing the provided value with the provided
 305  * callback, according to the algorithm of `Array::reduce`.
 306  */
 307 export const reduce = createCallableFunction(arrayPrototype.reduce);
 308
 309 /**
 310  * Reverses the provided value according to the algorithm of
 311  * `Array::reverse`.
 312  */
 313 export const reverse = createCallableFunction(arrayPrototype.reverse);
 314
 315 /**
 316  * Shifts the provided value according to the algorithm of
 317  * `Array::shift`.
 318  */
 319 export const shift = createCallableFunction(arrayPrototype.shift);
 320
 321 /**
 322  * Returns a slice of the provided value according to the algorithm of
 323  * `Array::slice`.
 324  */
 325 export const slice = createCallableFunction(arrayPrototype.slice);
 326
 327 /**
 328  * Sorts the provided value in‐place according to the algorithm of
 329  * `Array::sort`.
 330  */
 331 export const sort = createCallableFunction(arrayPrototype.sort);
 332
 333 /**
 334  * Splices into and out of the provided value according to the
 335  * algorithm of `Array::splice`.
 336  */
 337 export const splice = createCallableFunction(arrayPrototype.splice);
 338
 339 /**
 340  * Unshifts the provided value according to the algorithm of
 341  * `Array::unshift`.
 342  */
 343 export const unshift = createCallableFunction(arrayPrototype.unshift);