every() method
Runs the given function for each item in the array, and returns true if it returns true for each item
let number = [1,2,3,4,5,6,7,8,9,10,11,12,1,31,21];
Example 1:
let everyResult = number.every(function(item,index,array){ console.log('item:'+item); //item:1 console.log('index:'+index); //index:0 console.log('array:'+array); //array:1,2,3,4,5,6,7,8,9,10,11,12,1,31,21 }); console.log(everyResult); // false
Example 2:
let everyResult2 = number.every(function(item,index,array){ return item>2; }); console.log(everyResult2); // false
Example 3:
let everyResult3 = number.every(function(item,index,array){ return item>=1; }); console.log(everyResult3); // true
some() method
Runs the given function for each item in the array, and returns true if it returns true for any item.
Example 1:
let someResult = number.some(function(item,index,array){ console.log('item:'+item); //Output every item console.log('index:'+index); console.log('array:'+array); }); console.log(someResult); // false
Example 2:
let someResult2 = number.some(function(item,index,array){ return item>2; }); console.log(someResult2); // true
Example 3:
let someResult3 = number.some(function(item,index,array){ return item<0; }); console.log(someResult3); // false
filter() method
Run the given function for each item in the array, and the return function returns an array of items that are true.
Example 1:
let filetResult = number.filter(function(item,index,array){ console.log('item:'+item); console.log('index:'+index); console.log('array:'+array);//Loop out all items }); console.log(filetResult);// Empty array
Example 2:
let filetResult2 = number.filter(function(item,index,array){ return item>4; }); console.log(filetResult2);// (10) [5, 6, 7, 8, 9, 10, 11, 12, 31, 21]
Example 3:
let filetResult3 = number.filter(function(item,index,array){ return item<1; }); console.log(filetResult3);//Empty array
map() method
Run the given function for each item in the array, and return the array composed of the results of each function call.
example:
let mapResult = number.map(function(item,index,array){ return item*2; }); console.log(mapResult);//(15) [2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 2, 62, 42]
forEach() method
Runs the given function for each item in the array with no return value.
numbers.forEach(function(item,index,array){ //Do something });