CODE EXAMPLE FOR JAVASCRIPT

JS Reduce example

const grades = [60, 55, 80, 90, 99, 92, 75, 72];
const total = grades.reduce(sum);
function sum(acc, grade) {  
return acc + grade;
}
const count = grades.length;
const letterGradeCount = grades.reduce(groupByGrade, {});
function groupByGrade(acc, grade) {  
const { a = 0, b = 0, c = 0, d = 0, f = 0 } = acc;  
if (grade >= 90) {    
return { ...acc, a: a + 1 };  
} else if (grade >= 80) {    
return { ...acc, b: b + 1 };  
} else if (grade >= 70) {    return { ...acc, c: c + 1 };  
} else if (grade >= 60) {    return { ...acc, d: d + 1 };  
} else {    return { ...acc, f: f + 1 };  }}
console.log(total, total / count, letterGradeCount);