检查方法返回未定义

Question

I have read the documentation. and research about some check package tutorial. meteor docs , try to install again the check package atmospherejs , and look its to simple to use it. But

everytime I try something like:

check("this is string",String); //return undefined

var objectTest = { some : 0 };
check(objectTest, Object); //undefined
check(objectTest.some, Number); //undefined

Its always returning undefined and I dont know why, the check function its there if I write on the chrome console check return

function (value, pattern) {                                              // 19
  // Record that check got called, if somebody cared.                            // 20
  //                                                                             // 21
  // We use getOrNullIfOutsideFiber so that it's OK to call check()              // 22
  // from non-Fiber server contexts; the downside is that if you forget to       // 23
  // bindEnvironment on some random callback in your method/publisher,           // 24
  // it might not find the argumentChecker and you'll get an error about         // 25
  // not checking an argument that it looks like you're checking (instead        // 26
  // of just getting a "Node code must run in a Fiber" error).                   // 27
  var argChecker = currentArgumentChecker.getOrNullIfOutsideFiber();             // 28
  if (argChecker)                                                                // 29
    argChecker.checking(value);                                                  // 30
  try {                                                                          // 31
    checkSubtree(value, pattern);                                                // 32
  } catch (err) {                                                                // 33
    if ((err instanceof Match.Error) && err.path)                                // 34
      err.message += " in field " + err.path;                                    // 35
    throw err;                                                                   // 36
  }                                                                              // 37
}

so the function its there but i dont know how to use it... do you have any idea why its returning undefined? (btw I google "Meteor check method return undefined" without success)

thanks for the support.

//Im using iron route if its matter for some reason //Im not using the function inside of Metero.publish or Meteor.methods

Answer 1

check doesn't return anything. That's why it always seems to be undefined.

It throws an exception if the value does not match the pattern. If the value matches the pattern, then it doesn't.

So instead of using if (check(...)) { , you would write code like this:

function sample(name) {
    check(name, String);
    // code down here won't run if name is not a string
    return name.toUpperCase();
}