Question

How to fill all the elements of an array from a start index to an end index with a value with Array.fill() in JavaScript

Answer 1

var arr = [1, 2, 3, 4, 5];
 
arr.fill(3);
for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 3
arr[1] = 3
arr[2] = 3
arr[3] = 3
arr[4] = 3

*/

 

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Answer 2

var arr = [1, 2, 3, 4, 5];
 
arr.fill(3, 1);
for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 1
arr[1] = 3
arr[2] = 3
arr[3] = 3
arr[4] = 3

*/

 

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Answer 3

var arr = [1, 2, 3, 4, 5];
 
arr.fill(3, 1, 2);
for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 1
arr[1] = 3
arr[2] = 3
arr[3] = 4
arr[4] = 5

*/

 

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Answer 4

var arr = [1, 2, 3, 4, 5];
 
arr.fill(3, 1, 1);
for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 1
arr[1] = 2
arr[2] = 3
arr[3] = 4
arr[4] = 5

*/

 

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Answer 5

var arr = [1, 2, 3, 4, 5];
 
arr.fill(3, -3);
for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 1
arr[1] = 2
arr[2] = 3
arr[3] = 3
arr[4] = 3

*/

 

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Answer 6

var arr = [1, 2, 3, 4, 5];
 
arr.fill(3, -1);
for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 1
arr[1] = 2
arr[2] = 3
arr[3] = 4
arr[4] = 3

*/

 

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Answer 7

var arr = Array(4).fill(3);

for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 3
arr[1] = 3
arr[2] = 3
arr[3] = 3

*/

 

70+ SQL courses for beginners and professionals