Nodejs Array Map map(projectionFunction)

Method Source Code

Array.prototype.map = function(projectionFunction) {
   var results = [];
   this.forEach(function(itemInArray) {

      // ------------ INSERT CODE HERE! ----------------------------
      // Apply the projectionFunction to each item in the array and add
      // each result to the results array.
      // Note: you can add items to an array with the push() method.
      // ------------ INSERT CODE HERE! ----------------------------
    results.push(projectionFunction(itemInArray));
   });//from ww w .  ja va  2 s .  co m

   return results;
};

 var answer = JSON.stringify([1,2,3].map(function(x) { return x + 1; })) === '[2,3,4]';

 console.log(answer);

Related

1. map(projectionFunction)

   Array.prototype.map = function(projectionFunction) {
     var results = [];
     this.forEach(function(itemInArray) {
       results.push(itemInArray+1);
     });
     console.log(results);
     return results;
   };
   

2. map(projectionFunction)

   Array.prototype.map = function (projectionFunction) {
     var results = [];
     this.forEach(function (itemInArray) {
       results.push(projectionFunction(itemInArray));
     });
     return results;
   };
   

3. map(projectionFunction)

   Array.prototype.map = function(projectionFunction) {
     var results = [];
     this.forEach(function(itemInArray) {
       results.push(projectionFunction(itemInArray));
     });
     return results;
   };
   

4. map(projectionFunction)

   Array.prototype.map = function(projectionFunction) {
     var results = [];
     this.forEach(function(itemInArray) {
       results.push(projectionFunction(itemInArray));
     });
     return results;
   };
   console.log(JSON.stringify([1,2,3].map(function(x) { return x + 1; }))) 
   

5. map(projectionFunction)

   Array.prototype.map = function(projectionFunction) {
     var results = [];
     this.forEach(function(itemInArray) {
       results.push(projectionFunction(itemInArray));
     });
     return results;
   };
   

6. map(projectionFunction)

   Array.prototype.map = function(projectionFunction) {
     var results = [];
     this.forEach(itemInArray => results.push(projectionFunction(itemInArray)) );
     return results;
   };
   

7. map(projectionFunction)

   Array.prototype.map = function (projectionFunction) {
     var results = [];
     this.forEach(function (itemInArray) {
       results.push(projectionFunction(itemInArray));
     });
     return results;
   };
   

8. map(projectionFunction)

   Array.prototype.map = function(projectionFunction) {
     var results = [];
     this.forEach(function(itemInArray) {
     });
     return results;
   };
   JSON.stringify(
     [1,2,3].map(function(x) {
       return x + 1;
   ...
   

9. map(testFunction)

   Array.prototype.map = function(testFunction){
     var result = [];
     this.forEach(function(item){
       result.push(testFunction(item));
     })
     return result;