let a = '{"type":"discussion-post","action":"created","url":"https://lost-cities-keeper.fandom.com/f/p/4400000000000277948/r/4400000000002061507","userName":"AnonymousWikiEditor","snippet":"Omg I screamed when Ariana posted the engagement…","size":66,"category":"Off-Topic"}';

let b = JSON.parse(a);

 console.log(b.url);

let a = '{"type":"discussion-post","action":"created","url":"https://lost-cities-keeper.fandom.com/f/p/4400000000000277948/r/4400000000002061507","userName":"AnonymousWikiEditor","snippet":"Omg I screamed when Ariana posted the engagement…","size":66,"category":"Off-Topic"}';

let b = a.split('"url":"')[1];

b = b.split('","')[0];

console.log(b);

let a = '{"type":"discussion-post","action":"created","url":"https://lost-cities-keeper.fandom.com/f/p/4400000000000277948/r/4400000000002061507","userName":"AnonymousWikiEditor","snippet":"Omg I screamed when Ariana posted the engagement…","size":66,"category":"Off-Topic"}';

let regexp = /"url":"(https:\/\/.*?)"/g; 

let b = regexp.exec(a)[1];

console.log(b);