What is Higher Order Function?
A function inside another function and the return function itself is called a higher-order function.
Callback Function: — When a function is passed into a higher-order function is known as a callback function.
The function is a first-class citizen in javascript.
e.g.
console.log(“Start”);
const radius = [3, 4, 5, 6, 2, 7];
const calculate = (radius, logic) => {
const output = [];
for (i = 0; i < radius.length; i++) {
output.push(logic(radius[i]));
}
return output;
};
const area = (radius) => {
return Math.PI * radius * radius;
};
const circumference = (radius) => {
return 2 * Math.PI * radius;
};
const diameter = (radius) => {
return 2 * radius;
};
console.log(calculate(radius, area));
console.log(calculate(radius, circumference));
console.log(calculate(radius, diameter));
console.log(radius.map(area));
— — — — — — — The upper code is in higher-order function. — — — — — — -
_____ which is scalable, reusable , modularly
// — — -We can also write this code this type but it is not recommended — — — — —
_____________________________________________________________________________________
console.log(“Start”);
const radius = [3, 4, 5, 6, 2, 7];
const areaCalculate = function area(radius) {
const output = [];
for (i = 0; i < radius.length; i++) {
output.push(Math.PI * radius[i] * radius[i]);
}
return output;
};
console.log(areaCalculate(radius));
//____________________________________________
const circumferenceCalculate = function circumference(radius) {
const output = [];
for (i = 0; i < radius.length; i++) {
output.push(2 * Math.PI * radius[i]);
}
return output;
};
console.log(circumferenceCalculate(radius));
//________________________________________________
const diameter = function diameter(radius) {
const output = [];
for (i = 0; i < radius.length; i++) {
output.push(2 * radius[i]);
}
return output;
};
console.log(diameter(radius));
*/
