freecodecamp: Functional Programming

freecodecamp: Functional Programming, Learn About Functional Programming

note code to remember about this course

Learn About Functional Programming

"const tea4TeamFCC = getTea(40); // :("

Understand Functional Programming Terminology

"const tea4GreenTeamFCC = getTea(prepareGreenTea,27); // :(

const tea4BlackTeamFCC = getTea(prepareBlackTea,13); // :("

Understand the Hazards of Using Imperative Code

""

Avoid Mutations and Side Effects Using Functional Programming

" return fixedValue+1;"

Pass Arguments to Avoid External Dependence in a Function

"function incrementer (v) {

return v+1

// Add your code above this line

}

"

Refactor Global Variables Out of Functions

"// Add your code below this line

function add (a,bookName) {

let t=a.slice(0);

t.push(bookName);

return t;

// Add your code above this line

}

/* This function should remove a book from the list and return the list */

// New parameters should come before the bookName one

// Add your code below this line

function remove (a,bookName) {

let t=a.slice(0);

let n=t.indexOf(bookName);

if (n >= 0) {

t.splice(n, 1);

return t;

// Add your code above this line

}

}"

Use the map Method to Extract Data from an Array

"

// Add your code below this line

var rating = [];

rating= watchList.map((v)=>{

let obj = {'title':'','rating':0};

obj.title=v.Title;

obj.rating= v.imdbRating;

return obj;

});

// Add your code above this line"

Implement map on a Prototype

" var newArray = [];

// Add your code below this line

for(let i=0;i<this.length;i++){

newArray.push(callback(this[i]));

}

// Add your code above this line

return newArray;"

Use the filter Method to Extract Data from an Array

"// Add your code below this line

function isAdd(){

watchList.hasOwnProperty('Title') && watchList.hasOwnProperty('imdbRating');

return obj

}

var filteredList=watchList.filter((v)=>v.hasOwnProperty('Title') && v.imdbRating>=8.0).map(l=>{

let obj={'title':'','rating':0};

obj.title=l.Title;

obj.rating=l.imdbRating;

return obj;

});

// Add your code above this line"

Implement the filter Method on a Prototype

" // Add your code below this line

this.forEach(function(item){

if(callback(item))

newArray.push(item);

});

// Add your code above this line"

Return Part of an Array Using the slice Method

"return anim.slice(beginSlice,endSlice);"

Remove Elements from an Array Using slice Instead of splice

"// Add your code below this line

if(cities.length>=3)

return cities.slice(0,3);

// Add your code above this line"

Combine Two Arrays Using the concat Method

" // Add your code below this line

return original.concat(attach);

// Add your code above this line"

Add Elements to the End of an Array Using concat Instead of push

"return original.concat(newItem);"

Use the reduce Method to Analyze Data

"var averageRating=watchList.filter(v=>v.Director==='Christopher Nolan').map(v=>{return parseFloat(v.imdbRating)}).reduce((a,c,n,arr)=>a+ c/arr.length,0);"

Sort an Array Alphabetically using the sort Method

" // Add your code below this line

return arr.sort((a,b)=>a>b);

// Add your code above this line"

Return a Sorted Array Without Changing the Original Array

" // Add your code below this line

let tt= arr.slice(0);

let t=[];

return t.concat(tt.sort((a,b)=>a>b));

// Add your code above this line"

Split a String into an Array Using the split Method

"let reg=/\W/;

return str.split(reg);"

Combine an Array into a String Using the join Method

" // Add your code below this line

let reg=/\W/;

let t=str.split(reg);

return t.join(' ');

// Add your code above this line"

Apply Functional Programming to Convert Strings to URL Slugs

"return title.trim().toLowerCase().split(/\W+/).join("-"); "

Use the every Method to Check that Every Element in an Array Meets a Criteria

"return arr.every(function(v){return v>0;});"

Use the some Method to Check that Any Elements in an Array Meet a Criteria

"return arr.some(function(v){return v>0;});"

Introduction to Currying and Partial Application

" // Add your code below this line

return function(y){

return function(z){

return y+z+x;

}

}"