Nodejs Array Filter filter(predicateFunction)

Method Source Code

Array.prototype.filter = function(predicateFunction) {
   var results = [];
   this.forEach(function(itemInArray) {
      if(predicateFunction(itemInArray) == true)
      results.push(itemInArray);//ww  w  .  j av  a2s. c om
   });

   return results;
};

// JSON.stringify([1,2,3].filter(function(x) { return x > 2})) === "[3]"

Related

1. filter(predicate)

   Array.prototype.filter = function(predicate) {
     var result = []
     for ( var i = 0; i < this.length; i++) {
       if (predicate(this[i])) {
         result.push(this[i]);
     return result;
   

2. filter(predicate)

   Array.prototype.filter = function(predicate){
     return this.reduce(function(accumulator, value){
       return predicate(value) ? accumulator.concat(value) : accumulator;
     }, []);
   console.log([1, 2, 3, 4, 5].filter(function(val){
     return val % 2 === 0; 
   }));
   

3. filter(predicate)

   Array.prototype.filter = function (predicate) {
       let result = [];
       this.forEach(item => {
           if (predicate(item)) {
               result.push(item);
       })
       return result;
   };
   ...
   

4. filter(predicate)

   Array.prototype.filter = function(predicate) {
     var filtered_array = [];
     this.forEach(function (element, i) {
       if (predicate(element)) filtered_array.push(element);
     });
     return filtered_array;
   

5. filter(predicateFunction)

   Array.prototype.filter = function(predicateFunction) {
     var results = [];
     this.forEach(function(itemInArray) {
       if (predicateFunction(itemInArray)) {
       results.push(itemInArray);
     });
     return results;
   };
   ...
   

6. filter(predicateFunction)

   Array.prototype.filter = function(predicateFunction){
     var result = [];
     this.forEach(function(item){
       if(predicateFunction(item)) {
         result.push(item);
     })
     return result;
   Array.prototype.map = function(predicateFunction){
     var result = [];
     this.forEach(function(item){
       result.push(predicateFunction(item));
     })
     return result;
   var a = [1,2,3,4,5,6,7,8,9];
   a.map(function(x){
     return x*2;
   }).filter(function(x){
     if(x > 4) return true;
   })
   

7. filter(predicateFunction)

   var result = ['A','B','C','D','E','F'].filter(function(x) { 
     return x > 'C'
   });
   console.log(result);
   var outcome = JSON.stringify(result);
   console.log(outcome);
   var testOutCome = outcome === '["D","E","F"]';
   console.log(testOutCome);
   

8. filter(predicateFunction)

   Array.prototype.filter = function(predicateFunction) {
     var results = [];
     this.forEach(function(itemInArray) {
       if (predicateFunction(itemInArray)) {
       results.push(itemInArray);
     });
     return results;
   };
   ...
   

9. filter(predicateFunction)

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