
This article shows multiple ways to return the sum for an array of numbers in Javascript.
let’s declare an array as input
var myarray = [7, 8, 1, 9];
Output:
7+8+1+9=25
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Sum of an array of numbers in javascript
- use for index loop
for index, the loop is a basic loop in Any programming language.
It iterates an array using an index starting from zero until the length of the array is reached.
A temporary variable is created to sum each iterate array value and store it.
Here is an example code
var myarray = [7, 8, 1, 9];
var result = 0;
for (var i = 0; i < myarray.length; i++) {
result += myarray[i];
}
console.log(result); //25
- use the for-of loop ES6 provides a for-of loop to iterate an array of elements in another way.
Syntax:
for(index of array){
get element using array[i] syntax
}
Here is an example
var myarray = [7, 8, 1, 9];
var sum = 0;
for (var k in myarray) {
sum += myarray[k];
}
console.log(sum)
Output:
25
- use a forEach loop
Another way to iterate an array in javascript using the forEach
loop.
The forEach
loop accepts a callback with each element.
The callback can be a normal function or an arrow function in ES6.
Here is an example.
let result=0;
myarra.forEach(item => {
result+=item;
});
console.log(result) // 25
- use the lodash sum function
if you are using lodash in your project, It provides the sum() function that returns the addition of numbers in an array.
Here is a lodash sum function example.
var myarray = [7, 8, 1, 9];
result = _.sum(myarray);
console.log(result)// 25
- use array reduce function
Array provides reduce function and reduces the array elements.
It accepts a callback function.
Written call back function with arrow syntax in ES6 to the sum of the numbers.
Here is an example code
var myarray = [7, 8, 1, 9];
const sum = (first, second) => first + second
const result= myarray.reduce(sum);
console.log(result)// 25
Conclusion
As a result, Shown multiple ways to the addition of numbers to an array.