Arrays in javascript

 N.B- we can iterate an array using foreach and map in javascript like below-

var arrays = [1,2,3,4,5];

foreach():

arrays.forEach(function(cur){

    if(cur===1){

        break; //break and continue is illegal in foreach .

   }    console.log(cur);

});

Syntax: arrays.forEach(callback)

You are passing a callback function.

break only works inside actual loops.

map():

map() is meant to transform an array and return a new array.

arrays.map(function(cur){

    if(cur===2){

        break;    //break and continue is illegal in map.

    }

    console.log(cur);

});

so the solution is to use regular for loop.

const result = [1,2,3].map(function(cur){

    if(cur === 2){
        return 100;
    }

    return cur;
});

console.log(result);

Output: [1,100,3]

return only returns for that one callback execution, not the whole iteration.

//ES5

for(var i=0;i<arrays.length;i++){

    if(i===3){

        break;

    }

    console.log(arrays[i]);

}

//ES6

const arrays = [7,1,2,3,4,5];

for(const cur of arrays){

    if(cur===3){

        continue;

    }

    console.log(cur);

}

we can use for--of loop to iterate easily over an array in ES6.

filter():

filter() → keep only elements that match a condition.

const nums = [1,2,3,4];

const result = nums.filter(function(cur){
return cur > 2;
});

console.log(result);

output:[3,4]

It creates a new array containing only the elements that passed the condition.

find(): 

find() → returns first matching element only (single value)

const nums = [1,2,3,4,5];

const result = nums.find(function(cur){
    return cur > 2;
});

console.log(result);

Output: 3
It stops when first match is found.