occurance of the number in array in js code example
Example: how to count occurences in an array with javascript
// This function counts instances of elements in an array
// the return object has the array elements as keys
// and number of occurrences as it's value
const arrToInstanceCountObj = arr => arr.reduce((obj, e) => {
obj[e] = (obj[e] || 0) + 1;
return obj;
}, {});
arrToInstanceCountObj(['h', 'e', 'l', 'l', 'o', 'w', 'o', 'r', 'l', 'd'])
/*
{
h: 1,
e: 1,
l: 3,
o: 2,
w: 1,
r: 1,
d: 1,
}
*/