A mini clone of the Lodash library.
BEWARE: This library was published for learning purposes. It is not intended for use in production-grade software.
This project was created and published by me as part of my learnings at Lighthouse Labs.
Install it:
npm install @rahmatsaeedi/lotide
Require it:
const _ = require('@rahmatsaeedi/lotide');
Call it:
const results = _.tail([1, 2, 3]) // => [2, 3]
The following functions are currently implemented:
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assertEqual(actual, expected, suppressLogging = false): A custom assert function with emoji icons. Returns a Boolean value.assertEqual("Bootcamp", "Bootcamp") // => ✅ Assertion Passed: Bootcamp === Bootcamp // => true assertEqual(1, 1) // => ✅ Assertion Passed: 1 === 1 // => true
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countLetters(string): Returns an object containing count of every character in an input string. The -
countOnly(array, object): Takes in a collection of items and return an object containing counts of everything that the input object listed.
// Given const firstNames = [ "Karl", "Salima", "Agouhanna", "Fang", "Kavith", "Jason", "Salima", "Fang", "Joe" ]; countOnly(firstNames, { "Jason": true, "Karima": true, "Fang": true }); // => { Jason: 1, Fang: 2 }
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eqArrays(array1, array2): Takes in two arrays and returnstrueorfalse, based on a perfect match. It also works with nested arrays. -
eqObjects(object1, object2): Take in two objects, checks whether that the two are identical, and returns a boolean. Supports nested objects with premitive values, and nested arrays.eqObjects({ x: 1, y: 2, z: 'w' }, { x: 1, y: 2, z: 'w' }); // => true eqObjects({ y: 2, x: 1, z: 'w' }, { x: 1, y: 2, z: 'w' }); // => true eqObjects({ x: 1, y:{y: [[2, [2]]], z: {m:'w'}}}, { x: 1, y:{y: [[2, [2]]], z: {m:'w'}} }); // => true eqObjects({ x: 1, y: 2, z: 'w' }, { x: 1, y: 2, z: 'w', zz:'zz' }); // => false
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findKey(object, predicate): This method returns the key of the first element predicate returns truthy. Predicate takes (object[key], key, object).findKey({ "Blue Hill": { stars: 1 }, "Akaleri": { stars: 3 }, "noma": { stars: 2 }, "elBulli": { stars: 3 }, "Ora": { stars: 2 }, "Akelarre": { stars: 3 } }, x => x.stars === 2); // => "noma"
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findKeyByValue(object, value): Searches for a key in an object where its value matches a given value.const bestTVShowsByGenre = { sciFi: "The Expanse", comedy: "Brooklyn Nine-Nine", drama: "The Wire", drama2: "The Wire" }; findKeyByValue(bestTVShowsByGenre, "The Wire"); // Returns: 'drama' findKeyByValue(bestTVShowsByGenre, "That '70s Show"); // Returns: undefined
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findKeysByValue(object, value): Searches for keys in an object where its value matches a given value. Returns an array.const bestTVShowsByGenre = { sciFi: "The Expanse", comedy: "Brooklyn Nine-Nine", drama: "The Wire", drama2: "The Wire" }; findKeyByValue(bestTVShowsByGenre, "The Wire"); // Returns: [ 'drama', 'drama2' ] findKeyByValue(bestTVShowsByGenre, "That '70s Show"); // Returns: []
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flatten(array): Given an array with other arrays inside, this function can flatten it into a single-level array.flatten([1, 2, [3, 4], 5, [6]]) // => [1, 2, 3, 4, 5, 6] flatten([1, 2, [3, [[[[4]] , 5]]], 6, [7, 8, 9, 10]]) // => [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] flatten(["1", ["2", ["3"]]]) // => [ '1', '2', '3' ]
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head(array): Returns the head of an array. Returns 'undefined' for empty array.head([1, 2, 3]); // => 1 head([]); // => undefined
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letterPositions(string): Returns an object, containing all the indices in the string where each character is found. Indicies are zero-based.letterPositions("Hello hehehe"); /* Returns { H: [ 0 ], h: [ 6, 8, 10 ], e: [ 1, 7, 9, 11 ], l: [ 2, 3 ], o: [ 4 ], ' ': [ 5 ] } */
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map(array, callBack): Returns a new array based on the results of callback function.
Requires:- An array to map
- A callback function
const words = ["ground", "control", "to", "major", "tom"]; let firstLetters = map(words, word => word[0]); // Returns: ['g','c','t','m','t']
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middle(array): Takes in an array and return the middle-most element(s) of the given array.- For arrays with one or two elements, returns an empty array.
- For arrays with odd number of elements, an array containing a single middle element is returned.
- For arrays with an even number of elements, an array containing the two elements in the middle is returned.
middle([1]) // => [] middle([1, 2]) // => [] middle([1, 2, 3]) // => [2] middle([1, 2, 3, 4, 5]) // => [3] middle([1, 2, 3, 4]) // => [2, 3] middle([1, 2, 3, 4, 5, 6]) // => [3, 4]
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min(array): Returns the minimum of an array.let testArray = [5, 7, -8, 2, 4, 0, 8, -1, 54, 13]; min(testArray); // => -8
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tail(array): Returns the tail of an array. ie, everything after the first element.tail([1, 2, 3]); // => [2, 3]
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takeUntil(array, predicate): Creates a slice of array with elements taken from the beginning. Elements are taken until predicate returns falsey. The predicate is invoked with three arguments: (value, index, array).const data1 = [1, 2, 5, 7, 2, -1, 2, 4, 5]; const data2 = ["I've", "been", "to", "Hollywood", ",", "I've", "been", "to", "Redwood"]; const results1 = takeUntil(data1, x => x < 0); const results2 = takeUntil(data2, x => x === ','); // results1 = [1, 2, 5, 7, 2] // results2 = ["I've", "been", "to", "Hollywood"]
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without(array, itemsToRemoveArray): Will return a subset of a given array, removing unwanted elements.without([1, 2, 3], [1]) // => [2, 3] without([1, 2, 1, 3, 1], [1]) // => [2, 3] without(["1", "2", "3"], [1, 2, "3"]) // => ["1", "2"]
Testing requires installing Mocha & Chai. If everything is alright, then npm test should return the following:
#assertEqual
√ returns 'true' for 1===1
√ returns 'true' for 'bootcamp' === 'bootcamp'
√ returns 'false' for '7' === 7
#countLetters
√ return['g'] is 2 for input 'google...'
√ return['.'] is 3 for input 'google...'
#countOnly
√ return correct value
√ is case sensitive
√ returns 'undefined' for non-existant keys
#eqArrays
√ returns 'true' for same arrays
√ returns 'false' for different arrays
√ returns 'true' for same nested-arrays
√ returns 'true' for same mixed number-string nested-arrays
#eqObjects
√ returns 'true' for the same flat-objects with perimitive-values
√ returns 'false' for unlike simple flat-objects
√ returns 'true' for the same nested-obeject with nested-array values
√ returns 'true' for the same nested-obeject with nested-array values
#findKeyByValue
√ returns the correct key for string-valued values
√ returns the correct key for integer-valued values
√ returns 'undefined' if value is not in the object
#findKeysByValue
√ returns the correct keys for string-valued values
√ returns the correct keys for integer-valued values
√ returns '[]' if values is not in the object
#findKey
√ returns the correct key
√ returns 'undefined' if none-matches
#flatten
√ returns the correct array for integer-valued values
√ returns the correct keys for string-valued values
#head
√ returns 1 for [1, 2, 3]
√ returns 'Hello' for ['Hello', 'Lighthouse', 'Labs']
√ returns 'undefined' for []
#letterPositions
√ returns the correct position-arrays as an object
√ is case sensitive
√ returns 'undefined' for characters that don't exist in the string
√ works with special character: white-space
√ works with special characters: ~!@#$%^&*()_+|\=-`{}[]":;'<>?/.,
#map
√ returns correct output
#middle
√ returns empty-array if input-array has 1 element
√ returns empty-array if input-array has 2 elements
√ returns correct array for arrays with odd number of elements
√ returns correct array for arrays with even number of elements
#min
√ returns correct output for all positive valued array
√ returns correct output for all negative valued array
√ returns correct output for mixed valued array
#tail
√ returns the correct output for nonempty input-arrays
√ returns an empty array for empty input-array
√ returns an empty array for an array with single element in it
#takeUntil
√ returns the correct output for integer-valued input-arrays
√ returns the correct output for string-valued input-arrays
√ returns an empty array for an empty input-array and 'undefined' callback function
#without
√ returns the correct output for flat premitive-valued input-arrays
√ returns the correct output for nested-premitive-valued input-arrays
√ returns an empty array for an empty input-array
51 passing (49ms)