index.ts

/* !
 * type-detect
 * Copyright(c) 2013 jake luer <jake@alogicalparadox.com>
 * MIT Licensed
 */
const promiseExists = typeof Promise === 'function';

const globalObject = ((Obj) => {
  if (typeof globalThis === 'object') {
    return globalThis; // eslint-disable-line
  }
  Object.defineProperty(Obj, 'typeDetectGlobalObject', {
    get() {
      return this;
    },
    configurable: true,
  });
  // @ts-ignore
  const global = typeDetectGlobalObject; // eslint-disable-line
  // @ts-ignore
  delete Obj.typeDetectGlobalObject;
  return global;
})(Object.prototype);

const symbolExists = typeof Symbol !== 'undefined';
const mapExists = typeof Map !== 'undefined';
const setExists = typeof Set !== 'undefined';
const weakMapExists = typeof WeakMap !== 'undefined';
const weakSetExists = typeof WeakSet !== 'undefined';
const dataViewExists = typeof DataView !== 'undefined';
const symbolIteratorExists = symbolExists && typeof Symbol.iterator !== 'undefined';
const symbolToStringTagExists = symbolExists && typeof Symbol.toStringTag !== 'undefined';
const setEntriesExists = setExists && typeof Set.prototype.entries === 'function';
const mapEntriesExists = mapExists && typeof Map.prototype.entries === 'function';
const setIteratorPrototype = setEntriesExists && Object.getPrototypeOf(new Set().entries());
const mapIteratorPrototype = mapEntriesExists && Object.getPrototypeOf(new Map().entries());
const arrayIteratorExists = symbolIteratorExists && typeof Array.prototype[Symbol.iterator] === 'function';
const arrayIteratorPrototype = arrayIteratorExists && Object.getPrototypeOf([][Symbol.iterator]());
const stringIteratorExists = symbolIteratorExists && typeof String.prototype[Symbol.iterator] === 'function';
const stringIteratorPrototype = stringIteratorExists && Object.getPrototypeOf(''[Symbol.iterator]());
const toStringLeftSliceLength = 8;
const toStringRightSliceLength = -1;

/**
 * ### typeOf (obj)
 *
 * Uses `Object.prototype.toString` to determine the type of an object,
 * normalising behaviour across engine versions & well optimised.
 *
 * @param {Mixed} object
 * @return {String} object type
 * @api public
 */
export default function typeDetect(obj: unknown): string {
  /* ! Speed optimisation
   * Pre:
   *   string literal     x 3,039,035 ops/sec ±1.62% (78 runs sampled)
   *   boolean literal    x 1,424,138 ops/sec ±4.54% (75 runs sampled)
   *   number literal     x 1,653,153 ops/sec ±1.91% (82 runs sampled)
   *   undefined          x 9,978,660 ops/sec ±1.92% (75 runs sampled)
   *   function           x 2,556,769 ops/sec ±1.73% (77 runs sampled)
   * Post:
   *   string literal     x 38,564,796 ops/sec ±1.15% (79 runs sampled)
   *   boolean literal    x 31,148,940 ops/sec ±1.10% (79 runs sampled)
   *   number literal     x 32,679,330 ops/sec ±1.90% (78 runs sampled)
   *   undefined          x 32,363,368 ops/sec ±1.07% (82 runs sampled)
   *   function           x 31,296,870 ops/sec ±0.96% (83 runs sampled)
   */
  const typeofObj = typeof obj;
  if (typeofObj !== 'object') {
    return typeofObj;
  }

  /* ! Speed optimisation
   * Pre:
   *   null               x 28,645,765 ops/sec ±1.17% (82 runs sampled)
   * Post:
   *   null               x 36,428,962 ops/sec ±1.37% (84 runs sampled)
   */
  if (obj === null) {
    return 'null';
  }

  /* ! Spec Conformance
   * Test: `Object.prototype.toString.call(window)``
   *  - Node === "[object global]"
   *  - Chrome === "[object global]"
   *  - Firefox === "[object Window]"
   *  - PhantomJS === "[object Window]"
   *  - Safari === "[object Window]"
   *  - IE 11 === "[object Window]"
   *  - IE Edge === "[object Window]"
   * Test: `Object.prototype.toString.call(this)``
   *  - Chrome Worker === "[object global]"
   *  - Firefox Worker === "[object DedicatedWorkerGlobalScope]"
   *  - Safari Worker === "[object DedicatedWorkerGlobalScope]"
   *  - IE 11 Worker === "[object WorkerGlobalScope]"
   *  - IE Edge Worker === "[object WorkerGlobalScope]"
   */
  if (obj === globalObject) {
    return 'global';
  }

  /* ! Speed optimisation
   * Pre:
   *   array literal      x 2,888,352 ops/sec ±0.67% (82 runs sampled)
   * Post:
   *   array literal      x 22,479,650 ops/sec ±0.96% (81 runs sampled)
   */
  if (
    Array.isArray(obj) &&
    (symbolToStringTagExists === false || !(Symbol.toStringTag in obj))
  ) {
    return 'Array';
  }

  // Not caching existence of `window` and related properties due to potential
  // for `window` to be unset before tests in quasi-browser environments.
  if (typeof window === 'object' && window !== null) {
    /* ! Spec Conformance
     * (https://html.spec.whatwg.org/multipage/browsers.html#location)
     * WhatWG HTML$7.7.3 - The `Location` interface
     * Test: `Object.prototype.toString.call(window.location)``
     *  - IE <=11 === "[object Object]"
     *  - IE Edge <=13 === "[object Object]"
     */
    if (typeof (window as any).location === 'object' && obj === (window as any).location) {
      return 'Location';
    }

    /* ! Spec Conformance
     * (https://html.spec.whatwg.org/#document)
     * WhatWG HTML$3.1.1 - The `Document` object
     * Note: Most browsers currently adher to the W3C DOM Level 2 spec
     *       (https://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-26809268)
     *       which suggests that browsers should use HTMLTableCellElement for
     *       both TD and TH elements. WhatWG separates these.
     *       WhatWG HTML states:
     *         > For historical reasons, Window objects must also have a
     *         > writable, configurable, non-enumerable property named
     *         > HTMLDocument whose value is the Document interface object.
     * Test: `Object.prototype.toString.call(document)``
     *  - Chrome === "[object HTMLDocument]"
     *  - Firefox === "[object HTMLDocument]"
     *  - Safari === "[object HTMLDocument]"
     *  - IE <=10 === "[object Document]"
     *  - IE 11 === "[object HTMLDocument]"
     *  - IE Edge <=13 === "[object HTMLDocument]"
     */
    if (typeof (window as any).document === 'object' && obj === (window as any).document) {
      return 'Document';
    }

    if (typeof (window as any).navigator === 'object') {
      /* ! Spec Conformance
       * (https://html.spec.whatwg.org/multipage/webappapis.html#mimetypearray)
       * WhatWG HTML$8.6.1.5 - Plugins - Interface MimeTypeArray
       * Test: `Object.prototype.toString.call(navigator.mimeTypes)``
       *  - IE <=10 === "[object MSMimeTypesCollection]"
       */
      if (typeof (window as any).navigator.mimeTypes === 'object' &&
          obj === (window as any).navigator.mimeTypes) {
        return 'MimeTypeArray';
      }

      /* ! Spec Conformance
       * (https://html.spec.whatwg.org/multipage/webappapis.html#pluginarray)
       * WhatWG HTML$8.6.1.5 - Plugins - Interface PluginArray
       * Test: `Object.prototype.toString.call(navigator.plugins)``
       *  - IE <=10 === "[object MSPluginsCollection]"
       */
      if (typeof (window as any).navigator.plugins === 'object' &&
          obj === (window as any).navigator.plugins) {
        return 'PluginArray';
      }
    }

    if ((typeof (window as any).HTMLElement === 'function' ||
        typeof (window as any).HTMLElement === 'object') &&
        obj instanceof (window as any).HTMLElement) {
      /* ! Spec Conformance
      * (https://html.spec.whatwg.org/multipage/webappapis.html#pluginarray)
      * WhatWG HTML$4.4.4 - The `blockquote` element - Interface `HTMLQuoteElement`
      * Test: `Object.prototype.toString.call(document.createElement('blockquote'))``
      *  - IE <=10 === "[object HTMLBlockElement]"
      */
      if ((obj as any).tagName === 'BLOCKQUOTE') {
        return 'HTMLQuoteElement';
      }

      /* ! Spec Conformance
       * (https://html.spec.whatwg.org/#htmltabledatacellelement)
       * WhatWG HTML$4.9.9 - The `td` element - Interface `HTMLTableDataCellElement`
       * Note: Most browsers currently adher to the W3C DOM Level 2 spec
       *       (https://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-82915075)
       *       which suggests that browsers should use HTMLTableCellElement for
       *       both TD and TH elements. WhatWG separates these.
       * Test: Object.prototype.toString.call(document.createElement('td'))
       *  - Chrome === "[object HTMLTableCellElement]"
       *  - Firefox === "[object HTMLTableCellElement]"
       *  - Safari === "[object HTMLTableCellElement]"
       */
      if ((obj as any).tagName === 'TD') {
        return 'HTMLTableDataCellElement';
      }

      /* ! Spec Conformance
       * (https://html.spec.whatwg.org/#htmltableheadercellelement)
       * WhatWG HTML$4.9.9 - The `td` element - Interface `HTMLTableHeaderCellElement`
       * Note: Most browsers currently adher to the W3C DOM Level 2 spec
       *       (https://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-82915075)
       *       which suggests that browsers should use HTMLTableCellElement for
       *       both TD and TH elements. WhatWG separates these.
       * Test: Object.prototype.toString.call(document.createElement('th'))
       *  - Chrome === "[object HTMLTableCellElement]"
       *  - Firefox === "[object HTMLTableCellElement]"
       *  - Safari === "[object HTMLTableCellElement]"
       */
      if ((obj as any).tagName === 'TH') {
        return 'HTMLTableHeaderCellElement';
      }
    }
  }

  /* ! Speed optimisation
  * Pre:
  *   Float64Array       x 625,644 ops/sec ±1.58% (80 runs sampled)
  *   Float32Array       x 1,279,852 ops/sec ±2.91% (77 runs sampled)
  *   Uint32Array        x 1,178,185 ops/sec ±1.95% (83 runs sampled)
  *   Uint16Array        x 1,008,380 ops/sec ±2.25% (80 runs sampled)
  *   Uint8Array         x 1,128,040 ops/sec ±2.11% (81 runs sampled)
  *   Int32Array         x 1,170,119 ops/sec ±2.88% (80 runs sampled)
  *   Int16Array         x 1,176,348 ops/sec ±5.79% (86 runs sampled)
  *   Int8Array          x 1,058,707 ops/sec ±4.94% (77 runs sampled)
  *   Uint8ClampedArray  x 1,110,633 ops/sec ±4.20% (80 runs sampled)
  * Post:
  *   Float64Array       x 7,105,671 ops/sec ±13.47% (64 runs sampled)
  *   Float32Array       x 5,887,912 ops/sec ±1.46% (82 runs sampled)
  *   Uint32Array        x 6,491,661 ops/sec ±1.76% (79 runs sampled)
  *   Uint16Array        x 6,559,795 ops/sec ±1.67% (82 runs sampled)
  *   Uint8Array         x 6,463,966 ops/sec ±1.43% (85 runs sampled)
  *   Int32Array         x 5,641,841 ops/sec ±3.49% (81 runs sampled)
  *   Int16Array         x 6,583,511 ops/sec ±1.98% (80 runs sampled)
  *   Int8Array          x 6,606,078 ops/sec ±1.74% (81 runs sampled)
  *   Uint8ClampedArray  x 6,602,224 ops/sec ±1.77% (83 runs sampled)
  */
  const stringTag = (symbolToStringTagExists && (obj as any)[Symbol.toStringTag]);
  if (typeof stringTag === 'string') {
    return stringTag;
  }

  const objPrototype = Object.getPrototypeOf(obj);
  /* ! Speed optimisation
  * Pre:
  *   regex literal      x 1,772,385 ops/sec ±1.85% (77 runs sampled)
  *   regex constructor  x 2,143,634 ops/sec ±2.46% (78 runs sampled)
  * Post:
  *   regex literal      x 3,928,009 ops/sec ±0.65% (78 runs sampled)
  *   regex constructor  x 3,931,108 ops/sec ±0.58% (84 runs sampled)
  */
  if (objPrototype === RegExp.prototype) {
    return 'RegExp';
  }

  /* ! Speed optimisation
  * Pre:
  *   date               x 2,130,074 ops/sec ±4.42% (68 runs sampled)
  * Post:
  *   date               x 3,953,779 ops/sec ±1.35% (77 runs sampled)
  */
  if (objPrototype === Date.prototype) {
    return 'Date';
  }

  /* ! Spec Conformance
   * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-promise.prototype-@@tostringtag)
   * ES6$25.4.5.4 - Promise.prototype[@@toStringTag] should be "Promise":
   * Test: `Object.prototype.toString.call(Promise.resolve())``
   *  - Chrome <=47 === "[object Object]"
   *  - Edge <=20 === "[object Object]"
   *  - Firefox 29-Latest === "[object Promise]"
   *  - Safari 7.1-Latest === "[object Promise]"
   */
  if (promiseExists && objPrototype === Promise.prototype) {
    return 'Promise';
  }

  /* ! Speed optimisation
  * Pre:
  *   set                x 2,222,186 ops/sec ±1.31% (82 runs sampled)
  * Post:
  *   set                x 4,545,879 ops/sec ±1.13% (83 runs sampled)
  */
  if (setExists && objPrototype === Set.prototype) {
    return 'Set';
  }

  /* ! Speed optimisation
  * Pre:
  *   map                x 2,396,842 ops/sec ±1.59% (81 runs sampled)
  * Post:
  *   map                x 4,183,945 ops/sec ±6.59% (82 runs sampled)
  */
  if (mapExists && objPrototype === Map.prototype) {
    return 'Map';
  }

  /* ! Speed optimisation
  * Pre:
  *   weakset            x 1,323,220 ops/sec ±2.17% (76 runs sampled)
  * Post:
  *   weakset            x 4,237,510 ops/sec ±2.01% (77 runs sampled)
  */
  if (weakSetExists && objPrototype === WeakSet.prototype) {
    return 'WeakSet';
  }

  /* ! Speed optimisation
  * Pre:
  *   weakmap            x 1,500,260 ops/sec ±2.02% (78 runs sampled)
  * Post:
  *   weakmap            x 3,881,384 ops/sec ±1.45% (82 runs sampled)
  */
  if (weakMapExists && objPrototype === WeakMap.prototype) {
    return 'WeakMap';
  }

  /* ! Spec Conformance
   * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-dataview.prototype-@@tostringtag)
   * ES6$24.2.4.21 - DataView.prototype[@@toStringTag] should be "DataView":
   * Test: `Object.prototype.toString.call(new DataView(new ArrayBuffer(1)))``
   *  - Edge <=13 === "[object Object]"
   */
  if (dataViewExists && objPrototype === DataView.prototype) {
    return 'DataView';
  }

  /* ! Spec Conformance
   * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%mapiteratorprototype%-@@tostringtag)
   * ES6$23.1.5.2.2 - %MapIteratorPrototype%[@@toStringTag] should be "Map Iterator":
   * Test: `Object.prototype.toString.call(new Map().entries())``
   *  - Edge <=13 === "[object Object]"
   */
  if (mapExists && objPrototype === mapIteratorPrototype) {
    return 'Map Iterator';
  }

  /* ! Spec Conformance
   * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%setiteratorprototype%-@@tostringtag)
   * ES6$23.2.5.2.2 - %SetIteratorPrototype%[@@toStringTag] should be "Set Iterator":
   * Test: `Object.prototype.toString.call(new Set().entries())``
   *  - Edge <=13 === "[object Object]"
   */
  if (setExists && objPrototype === setIteratorPrototype) {
    return 'Set Iterator';
  }

  /* ! Spec Conformance
   * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%arrayiteratorprototype%-@@tostringtag)
   * ES6$22.1.5.2.2 - %ArrayIteratorPrototype%[@@toStringTag] should be "Array Iterator":
   * Test: `Object.prototype.toString.call([][Symbol.iterator]())``
   *  - Edge <=13 === "[object Object]"
   */
  if (arrayIteratorExists && objPrototype === arrayIteratorPrototype) {
    return 'Array Iterator';
  }

  /* ! Spec Conformance
   * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%stringiteratorprototype%-@@tostringtag)
   * ES6$21.1.5.2.2 - %StringIteratorPrototype%[@@toStringTag] should be "String Iterator":
   * Test: `Object.prototype.toString.call(''[Symbol.iterator]())``
   *  - Edge <=13 === "[object Object]"
   */
  if (stringIteratorExists && objPrototype === stringIteratorPrototype) {
    return 'String Iterator';
  }

  /* ! Speed optimisation
  * Pre:
  *   object from null   x 2,424,320 ops/sec ±1.67% (76 runs sampled)
  * Post:
  *   object from null   x 5,838,000 ops/sec ±0.99% (84 runs sampled)
  */
  if (objPrototype === null) {
    return 'Object';
  }

  return Object
    .prototype
    .toString
    .call(obj)
    .slice(toStringLeftSliceLength, toStringRightSliceLength);
}