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JavaScript Build a REST API With Express Building API Routes in Express Error Handling in Express

madison briggs
madison briggs
7,085 Points
Posted by madison briggs
madison briggs
7,085 Points

What is the -1 for?

I don't understand the first line of code in the error handler for the vote up/vote down. This line: if(req.params.dir.search(/^(up | down)$/) === -1 {

Jean Pumarol
Jean Pumarol
22,747 Points
Jean Pumarol
Jean Pumarol
22,747 Points

You also can use another method that is available in the String object. The method is called endsWith. There are other two methods called startsWith and includes. This methods make finding sub-strings extremely easy. Hope that helps.

var str = "Hello world, welcome to the universe.";
var n = str.endsWith("universe.");

Documentation: MDN - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith W3Schools - https://www.w3schools.com/Jsref/jsref_endswith.asp

1 Answer

Martin Lecke
Martin Lecke
14,385 Points
Martin Lecke
Martin Lecke
14,385 Points

This code line is using the string .search()-method. If there is no match found when using the method the number returned is -1 This is because .search() is returning the position number. So if the method doesn't find a match it cannot return 0 because that's also the first number in the string. Try it out in your console

"madison".search('i');
// will return number: 3

"madison".search('M');
// will return number: -1 because it doesnt exist in the string

Read more about .search() on w3c

Saud Tauqeer
Saud Tauqeer
Courses Plus Student 8,099 Points

what about the ^ and $? and the / \

Ovidiu Cotorogea
Ovidiu Cotorogea
12,998 Points
Ovidiu Cotorogea
Ovidiu Cotorogea
12,998 Points

It is a regex expression, The ^ marks a beginning of a string and $ marks the end of a string. You usually insert a regex expression inside '/' like /someExpression/. Check out this -> https://www.debuggex.com/cheatsheet/regex/javascript