Kate and Phils completed operators

src/operators.js

@@ -1,76 +1,98 @@
 // Rewrite function as arrow function
-function convertToNumber(string){
+const convertToNumber= (string) => +string;
   // function receives a string representation
   // of a number convert it to a number and return it
-}
+
 
 // Rewrite function as arrow function
-function convertToNegativeNumber(string){
+const convertToNegativeNumber = (string) => +string > 0 ? -string:+string;
   // function receives a string representation
   // of a number
 
   // convert string to number and return a negative version of the number
-}
 
 // Rewrite function as arrow function
-function invertBoolean(input){
+const invertBoolean = (input) => typeof input === "boolean" ? !input : input;
   // function receives one argument which could be of any type
 
   // if it is a boolean negate it, true -> false, false to true
 
   // if the input is not a boolean return the input
-}
+
 
 // Rewrite function as arrow function
-function convertToBoolean(list){
-  // Function receives an array of values which could be of any type
+const convertToBoolean = (list) => list.map(x=> !!x);
+  // Function  receives an array of values which could be of any type
 
   // Convert all values in array to boolean and return the array
-}
+
 
 // Rewrite function as arrow function
-function deleteStrings(list){
+const deleteStrings= (list) => list.map(item => typeof item === "string" ? undefined :item);
   // Function receives an array of strings and numbers
 
   // delete strings in array, (make them undefined)
 
   // return resulting array
-}
+
 
 // Rewrite function as arrow function
-function deleteYear(cars){
+const deleteYear=(cars) => {
+  for (i=0;i<cars.length;i++){
+      if (cars[i].year<1995) {
+          delete cars[i].year;
+      } 
+  } return cars;
+}
   // cars is an array of objects. Each object has a make, model and year property
 
   // For example { make: 'Ford', model: 'Fiesta', year: 1991 }
 
   // return an array of cars with year property deleted if the year is before 1995
-}
+
 
 // Rewrite function as arrow function
-function isBetween(number, from, to){
+const isBetween = (number, from, to) => (number >= from && number < to) ? true : false;
   // function receives three numbers as arguments
 
   // return true if number is equal to or greater than from and less than to
 
   // return false otherwise
-}
+
 
 // Rewrite function as arrow function
-function evens(a, b, c, d){
+const evens = (a, b, c, d) => !(a%2 + b%2 + c%2 + d%2);
   // function receives 4 numbers return true if all numbers are even and false otherwise
 
   // do not use if/else or ternary
-}
+
 
 // Rewrite function as arrow function
-function averageOfStrings(list){
+const reducer = (accumulator, currentValue) => accumulator + currentValue;
+
+const averageOfStrings = (list) => {
+  let strings = list.filter(item => typeof item === "string");
+  let stringsToNumbers = strings.map(item => +item);
+  return stringsToNumbers.reduce(reducer)/stringsToNumbers.length;
+}
+
   // function receives an array of numbers and string representation of numbers
 
   // calculate an average value of numbers represented as strings and return it.
-}
+
 
 // Rewrite function as arrow function
-function footballScores(results){
+const footballScores = (results)=> {
+  let winners=[];
+  for (i=0;i<results.length;i++) {
+      if (results[i].home>results[i].away) {
+          winners[i]="home";
+      } else if (results[i].home<results[i].away) {
+          winners[i]="away";
+      } else {
+          winners[i]="draw";
+      }
+  } return winners;
   // results is an array of football scores represented as objects
 
   // for example: [{home: 0, away: 2}, {home: 3, away: 1}, {home: 1, away: 1}]