what is different of set vs append

Question

In Javascript, URLSearchParams Is it different "set" between "append"?

const test = new URLSearchParams();
test.append("name", "Harry Potter");

const test = new URLSearchParams();
test.set("name", "Harry Potter");

^ different?

Answer 1

The difference becomes easy to see when you call the methods twice. With append , both values are included in the URL, while with set , any present value will be overridden.

const url = new URLSearchParams()
url.append("name", "Harry Potter")
url.append("name", "Hermione Granger")
url.toString() // "name=Harry+Potter&name=Hermione+Granger"

const url = new URLSearchParams()
url.set("name", "Harry Potter")
url.set("name", "Hermione Granger")
url.toString() // "name=Hermione+Granger"