typeforce
Another biased type checking solution for Javascript.
Exception messages may change between patch versions, as often the patch will change some behaviour that was unexpected and naturally it results in a different error message.
Examples
var typeforce = require('typeforce')
var element = { prop: 'foo' }
var elementNumber = { prop: 2 }
var array = [element, element, elementNumber]
typeforce('Array', array)
typeforce('Number', array)
typeforce(['Object'], array)
typeforce(typeforce.arrayOf('Object'), array)
typeforce({ prop: 'Number' }, elementNumber)
typeforce('?Number', 2)
typeforce('?Number', null)
typeforce(typeforce.maybe(typeforce.Number), 2)
typeforce(typeforce.maybe(typeforce.Number), null)
typeforce(typeforce.anyOf('String', 'Number'), 2)
typeforce(typeforce.allOf({ x: typeforce.Number }, { y: typeforce.Number }), {
x: 1,
y: 2
})
typeforce(typeforce.value(3.14), 3.14)
function LongString (value, strict) {
if (!typeforce.String(value)) return false
if (value.length !== 32) return false
return true
}
typeforce(LongString, '00000000000000000000000000000000')
typeforce(LongString, 'not long enough')
Protips:
typeforce(typeforce.Array, array)
var type = {
foo: 'Number',
bar: '?String'
}
var fastType = typeforce.compile(type)
typeforce({
x: 'Number'
}, { x: 1 }, true)
typeforce({
x: 'Number'
}, { x: 1, y: 2 }, true)
Protips (extended types):
typeforce(typeforce.tuple('String', 'Number'), ['foo', 1])
typeforce(typeforce.tuple('Number', 'Number'), ['not a number', 1])
typeforce(typeforce.map('Number'), {
'anyKeyIsOK': 1
})
typeforce(typeforce.map('Number', typeforce.HexN(8)), {
'deadbeef': 1,
'ffff0000': 2
})
function Foo () {
this.x = 2
}
typeforce(typeforce.quacksLike('Foo'), new Foo())
typeforce(typeforce.quacksLike('Foo'), new (function Foo() {}))
Protips (no throw)
var typeforce = require('typeforce/nothrow')
var value = 'foobar'
if (typeforce(typeforce.Number, value)) {
console.log(`${value} is a number`)
} else {
console.log(`Oops, ${typeforce.error.message}`)
}
Protips (async)
var typeforce = require('typeforce/async')
typeforce(typeforce.Number, value, function (err) {
if (err) return console.log(`Oops, ${typeforce.error.message}`)
console.log(`${value} is a number`) // never happens
})
WARNING: Be very wary of using the quacksLike type, as it relies on the Foo.name property.
If that property is mangled by a transpiler, such as uglifyjs, you will have a bad time.