JavaScript foreach Function Examples

    JavaScript foreach

    This article is written just to introduce you with Foreach loop and how you can efficiently use in different places. I hope you will able to understand it well and do let me know in the comment section if something is incorrect or can be added to make this post valuable.

    ForEach() function is used to iterate through the items which can be array.

    Array. (function(currentValue, index, arr), thisValue)

    Here function is the callback function and  currentValue is the element which is being processed, index is optional which meant to be the array index of the current element and arr is also option is the array object to which current element belongs to.

    JavaScript array foreach

    const numbers = [‘1234’, ‘2345’, ‘4563’, ‘4567’];

    numbers.forEach((numberindexarr) => {

      console.log(number,index, arr.length);

    if(index+1==arr.length)

    {

      console.log(“Length of array is “+arr.length);

    }

    });

    Output will be

    1234 0 4

    2345 1 4

    4563 2 4

    4567 3 4

    Length of array is 4

    JavaScript foreach example

    function func() {

        const items = [1, 2, 3];

        const mult = [];

          items.forEach(function(item){

            mult.push(item*item);

        });

          document.write(mult);

    }

    func();

    Output will be 1, 4, 9

    In the above example each element in the array is multiplied to itself in block (item*item), 1×1, 2×2, 3×3 and then pushed to another array which is mult.

    JavaScript foreach array of strings

    const arraystring = [‘A’, ‘B’, ‘C’, ‘D’];

    arraystring.forEach((letterindexarr) => {

      console.log(letter,index, arr);

    });

    Output will be

    A0

    (4) [ “A” ,”B” ,”C” ,”D” ]

    B1

    (4)[ “A” ,”B” ,”C” ,”D” ]

    C2

    (4)[ “A” ,”B” ,”C” ,”D” ]

    D3

    (4)[ “A” ,”B” ,”C” ,”D” ]

    JavaScript foreach break

    var Break = {};

    const numbers = [‘1’, ‘2’, ‘3’, ‘4’];

    try {

      numbers.forEach(function(el) {

        console.log(el);

        if (el == 2) throw Break;

      });

    } catch (e) {

      if (e !== Break) throw e;

    }

    Output will be

    1

    2

    JavaScript foreach break Example

    var Break = {};

    const arraystring = [‘Dog’, ‘Cat’, ‘Cow’, ‘Horse’];

    try {

      arraystring.forEach(function(el) {

        console.log(el);

        if (el == ‘Cow’) throw Break;

      });

    } catch (e) {

      if (e !== Break) throw e;

    }

    Output will be

    Dog

    Cat

    Cow

    JavaScript foreach continue

    const arraycar = [‘BMW’, ‘Nissan’, ‘Ram’, ‘Audi’];

    arraycar.forEach(function (carindex) {

      // If the car is Ram, skip it

      if (car === ‘Ram’) return;

      // Otherwise log it to the console

      console.log(car);

    });

    Output will be

    BMW

    Nissan

    Audi

    JavaScript foreach index

    const checkindex = [‘A@S’, ‘XCD’, ‘ERF’, ‘DFG’];

    checkindex.forEach(function (checkindex) {

      // If the word is ERF, check index

      if (check === ‘ERF’)

      {

    console.log(check +” has index “+index);

      }

     });

    Output will be ERF has index 2

    JavaScript foreach index undefined

    JavaScript foreach return

    JavaScript foreach async

    JavaScript foreach countdown

    function countdown(number){

      if (number < 1) {

        return [];

      } else {

        const array = countdown(number – 1);

        array.unshift(number);

        return array;

      }

    }

    console.log(countdown(6));

    Output

    (6)[,6 ,5 ,4 ,3 ,2 ,1] will be

    JavaScript foreach order

    const letters = [‘C’,’A’,’B’,’D’, ‘2’, ‘1’];

    letters.sort();

    console.log(letters)

    (6)[ “1” ,”2″ ,”A” ,”B” ,”C” ,”D” ]

     

    For More JavaScript

    Sum of Array

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