what is ... in javascript
function sum(...numbers) {
return numbers.reduce((accumulator, current) => {
return accumulator += current;
});
};
sum(1,2) // 3
sum(1,2,3,4,5) // 15what is ... in javascript
function sum(...numbers) {
return numbers.reduce((accumulator, current) => {
return accumulator += current;
});
};
sum(1,2) // 3
sum(1,2,3,4,5) // 15... in javascript
function sum(x, y, z) {
return x + y + z;
}
const numbers = [1, 2, 3];
console.log(sum(...numbers));
// expected output: 6
console.log(sum.apply(null, numbers));
// expected output: 6
/* Spread syntax (...) allows an iterable such as an array expression or string
to be expanded in places where zero or more arguments (for function calls)
or elements (for array literals) are expected, or an object expression to be
expanded in places where zero or more key-value pairs (for object literals)
are expected. */
// ... can also be used in place of `arguments`
// For example, this function will add up all the arguments you give to it
function sum(...numbers) {
let sum = 0;
for (const number of numbers)
sum += number;
return sum;
}
console.log(sum(1, 2, 3, 4, 5));
// Expected output: 15
// They can also be used together, but the ... must be at the end
console.log(sum(4, 5, ...numbers));
// Expected output: 15js !==
var x = 5;
// === equal value and equal type
// e.g. 1.
x === 5 returns true
// e.g. 2.
x === "5" returns false
// !== not equal value or not equal type
// e.g. 1.
x !== 5 returns false
// e.g. 2.
x !== "5" returns true
// e.g. 3.
x !== 8 returns truewhat does -= mean in JavaScript
/* JavaScript shorthand -=
-= is shorthand to subtract something from a
variable and store the result as that same variable.
*/
// The standard syntax:
var myVar = 5;
console.log(myVar) // 5
var myVar = myVar - 3;
console.log(myVar) // 2
// The shorthand:
var myVar = 5;
console.log(myVar) // 5
var myVar -= 3;
console.log(myVar) // 2Copyright © 2021 Codeinu
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