how to remove element from array in javascript
/* there are 3 ways to do so
1) pop(), which removes the last element
2) shift(), which removes the first element
3) splice(), which removes any element with a specified index.
of these only splice() takes parameters. the first parameter it takes is the
index of the element to be removed, an integer. the second is the number of
elements to be removed, again integer. the third and fourth etc. are optional,
which is to be used if you want to replace them. Example: */
let numbers = [1, 2, 3, 4, 5];
numbers.pop(); // removes 5
numbers.shift(); // removes 1
let threeIndex = numbers.indexOf(3); // used for long arrays
numbers.splice(threeIndex, 1); // without replacement
numbers.splice(threeIndex, 1, 7) // 3 will now be replaced by 7