javascript why to use try catch code example

Example 1: try catch in javascript

try {
  // Try to run this code 
}
catch(err) {
  // if any error, Code throws the error
}
finally {
  // Always run this code regardless of error or not
  //this block is optional
}

Example 2: js should i use try catch

One should avoid throw errors as the way to pass error conditions
around in applications.

The throw statement should only be used
"For this should never happen, crash and burn. Do not
recover elegantly in any way"

try catch however is used in situation where host objects
or ECMAScript may throw errors.

Example:
-------------------------------------
var json
try {
    json = JSON.parse(input)
} catch (e) {
    // invalid json input, set to null
    json = null
}
-------------------------------------