try catch throwing error in javascript

1try {
2  // Try to run this code 
3}
4catch(err) {
5  // if any error, Code throws the error
6}
7finally {
8  // Always run this code regardless of error or not
9  //this block is optional
10}

1var someNumber = 1;
2try {
3  someNumber.replace("-",""); //You can't replace a int
4} catch(err) {
5 console.log(err);
6}

1"The try...catch statement marks a block of statements to try and specifies"
2"a response should an exception be thrown."
3
4try {
5  nonExistentFunction();
6} catch (error) {
7  console.error(error);
8  // expected output: ReferenceError: nonExistentFunction is not defined
9  // Note - error messages will vary depending on browser
10}
11

1let json = '{ "age": 30 }'; // incomplete data
2
3try {
4
5  let user = JSON.parse(json); // <-- no errors
6  alert( user.name ); // no name!
7
8} catch (e) {
9  alert( "doesn't execute" );
10}

1try {
2
3  alert('Start of try runs');  // (1) <--
4
5  lalala; // error, variable is not defined!
6
7  alert('End of try (never reached)');  // (2)
8
9} catch(err) {
10
11  alert(`Error has occurred!`); // (3) <--
12
13}