have
v0.4.0
Published
Have your arguments, and validate it too. -- Slick arguments validator for all your js functions.
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HAVE.js
Have your arguments, and validate it too:
var have = require('have');
function safeFunc(id, options, callback) {
have(arguments,
{ id : 'string or number'
, options : 'optional object'
, callback : 'function'
});
}
HAVE.js gives you a mini-DSL to quickly validate your function arguments.
MINI-DSL
In order of precedence:
opt X|optional X
- Optional XX or Y
- Either X or YX a|X arr|x array
- Array of Xs|str|string
- Stringn|num|number
- Numberb|bool|boolean
- Booleanf|fun|func|function
- Functiona|arr|array
- Arrayo|obj|object
- Objectr|rx|regex|regexp
- RegExpd|date
- Date
These matchers can be combined. These are all valid HAVE.js matchers:
str or num array
- String or Array of Numbernum arr or str arr
- Array of Number or Array of Stringnum a a a a
- Array of Array of Array of Array of Numberopt str or num array
- Optional (String or Array of Number)
Have fun!
PARSED ARGUMENTS
The HAVE.js function also returns any parsed argument collected in a hash keyed to the same key as was given in the schema. You can inspect the returned object to more easily obtain the parsed value without having to duplicate the HAVE.js parsing logic in your code to extract them.
var have = require('have');
function safeFunc(id, options, callback) {
var args = have(arguments,
{ id : 'string or number'
, options : 'optional object'
, callback : 'function'
});
options = args.options || { some: 'value' };
// some stuff
someDb.loadById(args.id, options, args.callback);
};
For a more careful argument names parsing you can pass several schema.
var have = require('have');
function safeFunc() {
var args = have(arguments,
[ { id : 'string or number'
, options : 'optional object'
, callback : 'function'
}
, { query : 'object'
, options : 'optional object'
, callback : 'function'
}
]);
var options = args.options || { some: 'value' };
// some stuff
if (args.id) {
someDb.loadById(args.id, options, args.callback);
} else {
someDb.find(args.query, options, args.callback);
}
};
And use "strict" mode to fail for those extra arguments that do not match the schema.
var have = require('have');
function safeFunc(id, options, callback) {
var args = have.strict(arguments,
{ id : 'string or number'
, options : 'optional object'
, callback : 'function'
});
// some stuff
};
// This throws an AssertionError: Wrong argument "foo"
safeFunc('id', { key: 'value' }, cb, 'foo')
SOFT ASSERTS
If you are like me and you write a lot of method preconditions that should be turned off or atleast, should not throws in production, you can replace HAVE.js assert function like so:
var have = require('have');
have.assert(function(cond, message) {
if (!cond) {
console.log('WARN: assertion failed: ' + message);
}
});
This will replace the assert
function HAVE.js uses internally with your implementation
so if you want to completely turns assertion off, then just give it a no-op function.
SHORTERs
For those who like it short, the above example can also be written like this:
var have = require('have');
function safeFunc(id, options, callback) {
have(arguments, { id: 's or n', options: 'opt o', callback: 'f' });
}
This is not very readable, of course. But HAVE.js does not dictate your readability preference for you. So go wild if you think it is ok : )
LICENSE
BSD (if you don't like BSD, just contact me)
CHANGELOG
v0.3.0
- (credit: @wmakeev) The function now returns parsed arguments as a hash object.
v0.2.3
- Adds the forgotten
boolean
support.
v0.2.1 - v0.2.2
- Eat
null
andundefined
where optional argument is expected.
SUPPORT / CONTRIBUTE
Test with npm test
or make test
.
Just open a new GitHub issue or ping me @chakrit on Twitter.
Pull requests and feature suggestions totally welcome.
40 Chakrit Wichian
2 Makeev Vitaliy
1 Edmond Meinfelder