Function parameter handle or paremeter error control
Example 1: Just checking if all arguments were passed / defined.
const required = (name) => {
console.warn(`Parameter is required and its shuld be type of ${name}`);
};
// use of this
function add(a = required("number"), b = required("number")) {
return a + b;
}
Or
function add(number1, number2) {
if (arguments.length < 2) {
console.warn("Missing arguments");
}
return number1 + number2;
}
Or
function add(number1, number2) {
if (typeof number1 === "undefined") {
console.warn("First argument is missing / not defined");
}
if (typeof number2 === "undefined") {
console.warn("Second argument is missing / not defined");
}
return number1 + number2;
}
Example 2: make sure each argument is correct type.
function add(number1, number2) {
if (isNaN(number1)) {
console.warn("First argument is not a number");
}
if (isNaN(number2)) {
console.warn("Second argument is not a number");
}
return number1 + number2;
}
Example 3: make sure each argument is defined and of correct type
function add(number1, number2) {
if (typeof number1 === "undefined" || isNaN(number1)) {
console.warn("First argument is missing / not defined");
}
if (typeof number2 === "undefined" || isNaN(number2)) {
throw new TypeError("Second argument is missing / not defined");
}
return number1 + number2;
}
Example 4: create extarnal function for make sure each argument is defined and of correct type
function handleError() {
for (let i = 0; i < arguments.length || arguments.length == 0; i++) {
if (arguments[i] === undefined) {
return "No argument, This is required";
} else if (typeof arguments[i] != "number") {
return "Please Give me Number";
} else if (arguments[i] < 0) {
return "Please Give Positive Number";
}
}
return "noError";
}
A simple react project that contain a single page application (SPA) And a simple caculator to make some calculation and there is a section you can see some Math quotes. Ⓜ??