For general modules, you can check for existence before trying to load. In the following path
is whatever path you want to load and process()
is a function performing whatever processing you'd like on your module:
var fs = require("fs");
fs.exists(path, function (exists) {
if (exists) {
var foo = require(path);
process(foo);
}
else {
// Whatever needs to be done if it does not exist.
}
});
And remember that path
above must be an actual path, and not a module name to be later resolved by Node as a path.
For a JSON file specifically, with path
and process
having the same meanings as above:
fs.readFile(path, function (err, data) {
if (err) {
// Whatever you must do if the file cannot be read.
return;
}
var parsed = JSON.parse(data);
process(parsed);
});
You can also use try... catch
but keep in mind that v8 won't optimize functions that have try... catch
in them. With path
and process
meaning the same as above:
try {
var foo = require(path);
process(foo);
}
catch (e) {
if (e.code !== "MODULE_NOT_FOUND")
throw e; // Other problem, rethrow.
// Do what you need if the module does not exist.
}