bootstrap-vue/src/utils/array.js

BootstrapVue provides one of the most comprehensive implementations of Bootstrap 4 components and grid system for Vue.js and with extensive and automated WAI-ARIA accessibility markup.

// Production steps of ECMA-262, Edition 6, 22.1.2.1
// es6-ified by @alexsasharegan
if (!Array.from) {
  Array.from = (function () {
    const toStr = Object.prototype.toString
    const isCallable = fn => typeof fn === 'function' || toStr.call(fn) === '[object Function]'
    const toInteger = value => {
      const number = Number(value)
      if (isNaN(number)) {
        return 0
      }
      if (number === 0 || !isFinite(number)) {
        return number
      }
      return (number > 0 ? 1 : -1) * Math.floor(Math.abs(number))
    }
    const maxSafeInteger = Math.pow(2, 53) - 1
    const toLength = value => Math.min(Math.max(toInteger(value), 0), maxSafeInteger)

    // The length property of the from method is 1.
    return function from (arrayLike /*, mapFn, thisArg */) {
      // 1. Let C be the this value.
      const C = this

      // 2. Let items be ToObject(arrayLike).
      const items = Object(arrayLike)

      // 3. ReturnIfAbrupt(items).
      if (arrayLike == null) {
        throw new TypeError('Array.from requires an array-like object - not null or undefined')
      }

      // 4. If mapfn is undefined, then let mapping be false.
      const mapFn = arguments.length > 1 ? arguments[1] : void undefined
      let T

      if (typeof mapFn !== 'undefined') {
        // 5. else
        // 5. a If IsCallable(mapfn) is false, throw a TypeError exception.
        if (!isCallable(mapFn)) {
          throw new TypeError('Array.from: when provided, the second argument must be a function')
        }

        // 5. b. If thisArg was supplied, let T be thisArg; else let T be undefined.
        if (arguments.length > 2) {
          T = arguments[2]
        }
      }

      // 10. Let lenValue be Get(items, "length").
      // 11. Let len be ToLength(lenValue).
      const len = toLength(items.length)

      // 13. If IsConstructor(C) is true, then
      // 13. a. Let A be the result of calling the [[Construct]] internal method
      // of C with an argument list containing the single item len.
      // 14. a. Else, Let A be ArrayCreate(len).
      let A = isCallable(C) ? Object(new C(len)) : new Array(len)

      // 16. Let k be 0.
      let k = 0
      // 17. Repeat, while k < len… (also steps a - h)
      let kValue
      while (k < len) {
        kValue = items[k]
        if (mapFn) {
          A[k] = typeof T === 'undefined' ? mapFn(kValue, k) : mapFn.call(T, kValue, k)
        } else {
          A[k] = kValue
        }
        k += 1
      }
      // 18. Let putStatus be Put(A, "length", len, true).
      A.length = len
      // 20. Return A.
      return A
    }
  })()
}

// https://tc39.github.io/ecma262/#sec-array.prototype.find
// Needed for IE support
if (!Array.prototype.find) {
  // eslint-disable-next-line no-extend-native
  Object.defineProperty(Array.prototype, 'find', {
    value: function (predicate) {
      // 1. Let O be ? ToObject(this value).
      if (this == null) {
        throw new TypeError('"this" is null or not defined')
      }

      const o = Object(this)

      // 2. Let len be ? ToLength(? Get(O, "length")).
      const len = o.length >>> 0

      // 3. If IsCallable(predicate) is false, throw a TypeError exception.
      if (typeof predicate !== 'function') {
        throw new TypeError('predicate must be a function')
      }

      // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
      const thisArg = arguments[1]

      // 5. Let k be 0.
      let k = 0

      // 6. Repeat, while k < len
      while (k < len) {
        // a. Let Pk be ! ToString(k).
        // b. Let kValue be ? Get(O, Pk).
        // c. Let testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
        // d. If testResult is true, return kValue.
        const kValue = o[k]
        if (predicate.call(thisArg, kValue, k, o)) {
          return kValue
        }
        // e. Increase k by 1.
        k++
      }

      // 7. Return undefined.
      return undefined
    }
  })
}

if (!Array.isArray) {
  Array.isArray = arg => Object.prototype.toString.call(arg) === '[object Array]'
}

// Static
export const from = Array.from
export const isArray = Array.isArray

// Instance
export const arrayIncludes = (array, value) => array.indexOf(value) !== -1
export const arrayFind = (array, fn, thisArg) => array.find(fn, thisArg)
export function concat () {
  return Array.prototype.concat.apply([], arguments)
}