tests passed #1
tests passed #1
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| // Return the new array. | ||
| }; | ||
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| const reduce = (elements, cb, startingValue) => { |
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You can also do this for a starting value: (elements, cb, startingValue = elements.shift()) for the default value. This takes advantage of the ES6 default parameters.
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Unless of course you are avoiding modifying the input array
src/arrays.js
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| // Elements will be passed one by one into `cb`. | ||
| // `startingValue` is the starting value. If `startingValue` is undefined then make `elements[0]` the initial value. | ||
| if (startingValue === undefined) { | ||
| startingValue = (typeof elements[0]) === 'string' ? '' : 0; |
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Just make startingValue the first item from the array
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A reduce is supposed to have the first item in the array as its initial memo
| const map = (elements, cb) => { | ||
| // Produces a new array of values by mapping each value in list through a transformation function (iteratee). | ||
| // Return the new array. | ||
| return reduce(elements, (acc, v) => { |
src/arrays.js
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| /* Extra Credit */ | ||
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| function isArray(elements) { | ||
| return (Object.prototype.toString.call(elements) === '[object Array]'); |
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The preferred way of checking whether a variable is an array or not is this: Array.isArray(myVariable);
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Good job creating another function though
src/callbacks.js
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| // code here | ||
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| const foods = ['pineapple', 'mango', 'ribeye', 'curry', 'tacos', 'ribeye', 'mango']; | ||
| function firstItem(foods,f) { |
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I'd prefer it if you put a space between the parameters
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accustomed to getting a 'comma-spacing' error by the eslint configs I have been working with
src/callbacks.js
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| const foods = ['pineapple', 'mango', 'ribeye', 'curry', 'tacos', 'ribeye', 'mango']; | ||
| function firstItem(foods,f) { | ||
| return f(foods[0]) |
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This line should have a semicolon
src/callbacks.js
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| // code here | ||
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| function getLength(foods,f) { | ||
| return f(foods.length) |
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Make sure that you stay consistent. Inconsistent code is a mark of an inexperienced developer. It shows experience and discipline to keep your code consistent.
| return Object.keys(obj); | ||
| }; | ||
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| function isFunction(func) { |
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For the sake of consistency this should be written the same way the other functions are written.
tests/arrays.test.js
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| const result = arrayMethods.reduce(arr, callBackMockFn); | ||
| expect(result).toBe(25); | ||
| expect(callBackMockFn.mock.calls.length).toBe(4); | ||
| expect(callBackMockFn.mock.calls.length).toBe(5); |
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This test should not be modified. The memo in the reduce should be the first item from the array and so the callback would only be invoked 4 times.
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