# ga-wdi-pvd/lesson-notes

added final notes after delivering lesson

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deconstructionalism committed Jun 13, 2018
1 parent 13daf7d commit 40ab2fdd3c9e0ab062ad8f6551fab1bc3cdbf625
 @@ -212,4 +212,170 @@ students.map(text => `\${text.toUpperCase()}!`) ``` #### Lab Code Here is the code we used today while going over the Lab. - **`bin/for-each.js`** - ```js #!/usr/bin/env node 'use strict' // Example array const nums = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ] // 1. Find the sum of all elements in an array using named arrow function // CODE ALONG CODE GOES HERE // OLD SCHOOL WAY OF DOING THIS WITHOUT REDUCE let accumulator = 0 for (let i = 0; i < nums.length; i++) { accumulator = accumulator + nums[i] } console.log(accumulator) // USING REDUCE INSTEAD const reducer = (accumulator, currentVal) => accumulator + currentVal const sum = nums.reduce(reducer) console.log(sum) // USING REDUCE WITHOUT DECLARING A SEPARATE NAMED FUNCTION // notice that the names of the parameters for the reduce callback // can be whatever you want to call them (compare this code to the // previous section's code) sum = nums.reduce((prev, curr) => prev + curr) console.log(sum) // 2. Find the largest of all elements in an array using named arrow function // CODE ALONG CODE GOES HERE const largest = nums.reduce((prev, curr) => prev > curr ? prev : curr) console.log(largest) // 3. Find the total number of days in fridge for all the food in the fridge // using anonymous arrow function // start the count with 0 const fridge = [ { food: 'Carrots', daysInFridge: 32 }, { food: 'Onions', daysInFridge: 23 }, { food: 'Bell Peppers', daysInFridge: 16 }, { food: 'Soda', daysInFridge: 7 }, { food: 'Pizza', daysInFridge: 4 }, { food: 'Cake', daysInFridge: 3 } ] // CODE ALONG CODE GOES HERE const howLazyYouAre = (prev, curr) => { const numDays = curr.daysInFridge return prev + numDays } fridge.reduce(howLazyYouAre, 0) ``` - **`bin/map.js`** - ```js #!/usr/bin/env node 'use strict' // Starting array const developers = ['Mike', 'Toni', 'Jessica'] // Iterate using FOR loop to create an array of 'Hello ' for each student // Original array unchanged let developerGreetings = [] for (let i = 0; i < developers.length; i++) { developerGreetings.push('Hello ' + developers[i]) } // Iterate using .forEach to create an array of 'Hello ' for each student // Original array unchanged // note: forEach returns undefined developerGreetings = [] developers.forEach(developer => developerGreetings.push('Hello ' + developer)) // example of above code using standard JS function developers.forEach(function(developer) { developerGreetings.push('Hello ' + developer) }) // 1. Iterate using .map to create an array of 'Hello ' for each student // Original array unchanged // CODE ALONG CODE GOES HERE developerGreetings = developers.map(developer => `Hello \${developer}`) ``` - **`bin/reduce.js`** - ```js #!/usr/bin/env node 'use strict' // Example array const nums = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ] // 1. Find the sum of all elements in an array using named arrow function // CODE ALONG CODE GOES HERE // OLD SCHOOL WAY OF DOING THIS WITHOUT REDUCE let accumulator = 0 for (let i = 0; i < nums.length; i++) { accumulator = accumulator + nums[i] } console.log(accumulator) // USING REDUCE INSTEAD const reducer = (accumulator, currentVal) => accumulator + currentVal const sum = nums.reduce(reducer) console.log(sum) // USING REDUCE WITHOUT DECLARING A SEPARATE NAMED FUNCTION // notice that the names of the parameters for the reduce callback // can be whatever you want to call them (compare this code to the // previous section's code) sum = nums.reduce((prev, curr) => prev + curr) console.log(sum) // 2. Find the largest of all elements in an array using named arrow function // CODE ALONG CODE GOES HERE const largest = nums.reduce((prev, curr) => prev > curr ? prev : curr) console.log(largest) // 3. Find the total number of days in fridge for all the food in the fridge // using anonymous arrow function // start the count with 0 const fridge = [ { food: 'Carrots', daysInFridge: 32 }, { food: 'Onions', daysInFridge: 23 }, { food: 'Bell Peppers', daysInFridge: 16 }, { food: 'Soda', daysInFridge: 7 }, { food: 'Pizza', daysInFridge: 4 }, { food: 'Cake', daysInFridge: 3 } ] // CODE ALONG CODE GOES HERE const howLazyYouAre = (prev, curr) => { const numDays = curr.daysInFridge return prev + numDays } fridge.reduce(howLazyYouAre, 0) ```
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