I'm defining custom JavaScript exceptions like the code below. Is this proper? Isn't there a shorter way?
function InvalidModuleError(moduleName) {
TypeError.apply(this);
this.message = "module '" + moduleName + "' doesn't export any definitions";
this.name = 'InvalidModuleError';
};
InvalidModuleError.prototype = Object.create(TypeError.prototype);
function DuplicateModuleError(moduleName) {
TypeError.apply(this);
this.message = "module '" + moduleName + "' is already defined";
this.name = 'DuplicateModuleError';
};
DuplicateModuleError.prototype = Object.create(TypeError.prototype);
Edit: Eventually, after Oriol's suggestion, I've made a function that generates exceptions and looks like this:
function makeException(parentObject, parentClass, name, message) {
var shortName = name.split('.');
shortName = shortName[shortName.length - 1];
parentObject[shortName] = function() {
this.message = (typeof message === 'function') ? message.apply(null, arguments) : message;
};
parentObject[shortName].prototype = Object.create(parentClass.prototype, {'name': {'value': name}});
}
Your code can be simplified a bit:
function InvalidModuleError(moduleName) {
this.message = "module '" + moduleName + "' doesn't export any definitions";
}
InvalidModuleError.prototype = new Error();
InvalidModuleError.prototype.name = 'InvalidModuleError';
function DuplicateModuleError(moduleName) {
this.message = "module '" + moduleName + "' is already defined";
}
DuplicateModuleError.prototype = new Error();
DuplicateModuleError.prototype.name = 'DuplicateModuleError';
But if you want to have lots of custom exceptions, better use
function newModuleError(errorName, message) {
var moduleError = function(moduleName) {
this.message = message.replace('%s', moduleName);
};
moduleError.prototype = new Error();
moduleError.prototype.name = errorName;
return moduleError;
};
var InvalidModuleError = newModuleError('InvalidModuleError', "module '%s' doesn't export any definitions"),
DuplicateModuleError = newModuleError('DuplicateModuleError', "module '%s' is already defined");
To throw them:
throw new InvalidModuleError("moduleName1");
throw new DuplicateModuleError("moduleName2");