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Commit 601fc58

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added folder array methods library
1 parent a61cb35 commit 601fc58

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‎ARRAY METHODS LIBRARY/.gitignore

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node_modules

‎ARRAY METHODS LIBRARY/LICENSE

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MIT License
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Copyright (c) 2022 WebDevSimplified
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.

‎ARRAY METHODS LIBRARY/arrayMethods.js

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function forEach(array, cb) {
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for (let i = 0; i < array.length; i++) {
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cb(array[i], i, array)
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}
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}
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function map(array, cb) {
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const newArray = []
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for (let i = 0; i < array.length; i++) {
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newArray.push(cb(array[i], i, array))
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}
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return newArray
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}
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function filter(array, cb) {
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const newArray = []
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for (let i = 0; i < array.length; i++) {
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const element = array[i]
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if (cb(element, i, array)) newArray.push(element)
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}
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return newArray
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}
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function reduce(array, cb, initialValue) {
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let currentValue = initialValue
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for (let i = 0; i < array.length; i++) {
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const element = array[i]
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if (initialValue == null && i === 0) {
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currentValue = element
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} else {
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currentValue = cb(currentValue, element, i, array)
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}
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}
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return currentValue
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}
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function some(array, cb) {
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for (let i = 0; i < array.length; i++) {
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if (cb(array[i], i, array)) return true
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}
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return false
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}
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function every(array, cb) {
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for (let i = 0; i < array.length; i++) {
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if (!cb(array[i], i, array)) return false
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}
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return true
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}
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function flat(array, depth = 1) {
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const newArray = []
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for (let i = 0; i < array.length; i++) {
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const element = array[i]
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if (Array.isArray(element) && depth > 0) {
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newArray.push(...flat(element, depth - 1))
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} else {
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newArray.push(element)
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}
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}
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return newArray
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}
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function find(array, cb) {
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for (let i = 0; i < array.length; i++) {
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const element = array[i]
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if (cb(element, i, array)) return element
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}
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}
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module.exports = {
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forEach,
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map,
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filter,
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reduce,
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some,
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every,
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flat,
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find,
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}
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const {
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forEach,
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map,
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filter,
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reduce,
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some,
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every,
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flat,
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find,
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} = require("./arrayMethods.js")
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// const forEach = (a, ...args) => a.forEach(...args)
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// const map = (a, ...args) => a.map(...args)
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// const filter = (a, ...args) => a.filter(...args)
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// const reduce = (a, ...args) => a.reduce(...args)
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// const some = (a, ...args) => a.some(...args)
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// const every = (a, ...args) => a.every(...args)
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// const flat = (a, ...args) => a.flat(...args)
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// const find = (a, ...args) => a.find(...args)
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it("forEach", () => {
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const func = jest.fn()
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const startingArray = ["a", "b", "c"]
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forEach(startingArray, func)
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expect(func).toHaveBeenNthCalledWith(1, "a", 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, "b", 1, startingArray)
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expect(func).toHaveBeenNthCalledWith(3, "c", 2, startingArray)
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expect(func).toHaveBeenCalledTimes(3)
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})
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it("map", () => {
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const func = jest.fn((elem, index) => index * 2)
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const startingArray = ["a", "b", "c"]
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const newArray = map(startingArray, func)
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expect(newArray).toEqual([0, 2, 4])
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expect(func).toHaveBeenNthCalledWith(1, "a", 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, "b", 1, startingArray)
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expect(func).toHaveBeenNthCalledWith(3, "c", 2, startingArray)
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expect(func).toHaveBeenCalledTimes(3)
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})
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it("filter", () => {
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const func = jest.fn((elem, index) => elem === "a" || index === 2)
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const startingArray = ["a", "b", "c"]
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const newArray = filter(startingArray, func)
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expect(newArray).toEqual(["a", "c"])
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expect(func).toHaveBeenNthCalledWith(1, "a", 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, "b", 1, startingArray)
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expect(func).toHaveBeenNthCalledWith(3, "c", 2, startingArray)
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expect(func).toHaveBeenCalledTimes(3)
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})
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describe("reduce", () => {
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it("with a starting value", () => {
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const func = jest.fn((sum, elem) => sum + elem)
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const startingArray = [5, 3, 7]
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const total = reduce(startingArray, func, 4)
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expect(total).toEqual(19)
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expect(func).toHaveBeenNthCalledWith(1, 4, 5, 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, 9, 3, 1, startingArray)
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expect(func).toHaveBeenNthCalledWith(3, 12, 7, 2, startingArray)
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expect(func).toHaveBeenCalledTimes(3)
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})
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it("with no starting value", () => {
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const func = jest.fn((sum, elem) => sum + elem)
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const startingArray = [5, 3, 7]
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const total = reduce(startingArray, func)
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expect(total).toEqual(15)
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expect(func).toHaveBeenNthCalledWith(1, 5, 3, 1, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, 8, 7, 2, startingArray)
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expect(func).toHaveBeenCalledTimes(2)
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})
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})
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describe("some", () => {
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it("with a truthy value", () => {
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const func = jest.fn(elem => elem > 0)
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const startingArray = [-4, 3, 6]
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const result = some(startingArray, func)
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expect(result).toEqual(true)
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expect(func).toHaveBeenNthCalledWith(1, -4, 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, 3, 1, startingArray)
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expect(func).toHaveBeenCalledTimes(2)
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})
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it("with no truthy values", () => {
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const func = jest.fn(elem => elem > 0)
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const startingArray = [-4, -3, -6]
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const result = some(startingArray, func)
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expect(result).toEqual(false)
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expect(func).toHaveBeenNthCalledWith(1, -4, 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, -3, 1, startingArray)
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expect(func).toHaveBeenNthCalledWith(3, -6, 2, startingArray)
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expect(func).toHaveBeenCalledTimes(3)
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})
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})
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describe("every", () => {
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it("with a falsey value", () => {
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const func = jest.fn(elem => elem < 0)
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const startingArray = [-4, 3, 6]
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const result = every(startingArray, func)
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expect(result).toEqual(false)
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expect(func).toHaveBeenNthCalledWith(1, -4, 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, 3, 1, startingArray)
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expect(func).toHaveBeenCalledTimes(2)
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})
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it("with no falsey values", () => {
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const func = jest.fn(elem => elem < 0)
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const startingArray = [-4, -3, -6]
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const result = every(startingArray, func)
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expect(result).toEqual(true)
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expect(func).toHaveBeenNthCalledWith(1, -4, 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, -3, 1, startingArray)
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expect(func).toHaveBeenNthCalledWith(3, -6, 2, startingArray)
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expect(func).toHaveBeenCalledTimes(3)
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})
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})
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describe("flat", () => {
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it("with no value passed", () => {
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const startingArray = [1, [2, 3], [4, [5, 6, [7, 8]]]]
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const result = flat(startingArray)
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expect(result).toEqual([1, 2, 3, 4, [5, 6, [7, 8]]])
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})
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it("with a value passed", () => {
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const startingArray = [1, [2, 3], [4, [5, 6, [7, 8]]]]
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const result = flat(startingArray, 2)
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expect(result).toEqual([1, 2, 3, 4, 5, 6, [7, 8]])
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})
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it("with infinite passed", () => {
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const startingArray = [1, [2, 3], [4, [5, 6, [7, 8]]]]
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const result = flat(startingArray, Number.POSITIVE_INFINITY)
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expect(result).toEqual([1, 2, 3, 4, 5, 6, 7, 8])
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})
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})
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describe("find", () => {
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it("with no value found", () => {
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const func = jest.fn(elem => elem === 5)
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const startingArray = [1, 2, 3]
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const result = find(startingArray, func)
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expect(result).toBeUndefined()
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expect(func).toHaveBeenNthCalledWith(1, 1, 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, 2, 1, startingArray)
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expect(func).toHaveBeenNthCalledWith(3, 3, 2, startingArray)
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expect(func).toHaveBeenCalledTimes(3)
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})
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it("with a value found", () => {
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const func = jest.fn(elem => elem === 2)
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const startingArray = [1, 2, 3]
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const result = find(startingArray, func)
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expect(result).toEqual(2)
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expect(func).toHaveBeenNthCalledWith(1, 1, 0, startingArray)
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expect(func).toHaveBeenNthCalledWith(2, 2, 1, startingArray)
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expect(func).toHaveBeenCalledTimes(2)
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})
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})

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