Charge

Installation

> npm install ch-arge
var charge = require("ch-arge");

Example Usage

var charge = require("ch-arge");
 
function accountInfo(name, birthyear, data1, data2, userData) {
  // add new type that only accepts a or b
  charge.newType("ab", function (actual) {
    for (var i = 0; i < actual.length; i++) {
      if (actual[i] !== "a" or actual[i] !== "b") return false;
    }
  }, "ba");
 
  charge.newType("userData", function (actual) {
    return actual.length < 10;
  }, "ud");
 
  charge(name, String, {shouldThrow: false});
  charge(birthyear, "num Num|str,Str Date");
  charge(data1, "ab", {shouldThrow: true});
  charge(data2, "ba", {shouldThrow: true});
  charge(userData, "!null !undefined ud", {singleCheck: false});
 
  // logic that makes use of args
}

API

charge(actual, expected1[, expected2...][,opts])

Returns a boolean, depending on the actual matching any (or all if opts.singleCheck is off) of the given expected types.

• actual, the unknown type to be type asserted
• expected, may be either a Constructor or string, string may contain type aliases separated by |, ,, or (whitespace). ! prepended to the type alias will match the type if it isn't of that type. Multiple !! are supported.
• opts
  • shouldThrow, throws ArgError instance if actual fails to match a type. Defaults to true.
  • singleCheck, if false will pass if it matches all given expected types. Defaults to true.
  • message, if provided will override the default ArgError message. Must be a string, or else will error.

charge.newType ([name], checkFn, alias1 [,alias2] [,alias...])

Defines a new type known by name (if provided) and aliases. Returns name.

• name, for internal use and semantic debugging, if provided acts like an alias
• checkFn, first parameter must be prepared to receive the actual being tested for. The return should be boolean and determines if it is of that type.
• alias, A string value of names the type should be reference as.

charge.ArgError

The constructor for the error thrown if opts.shouldThrow is on, inherits from Error.

Bundled Types

Type	Aliases
Object	Object object Obj obj
Array	Array array Arr arr
Function	Function function Fn fn Func func
RegExp	RegExp regexp regExp Regexp
Date	Date date
Symbol	Symbol symbol Sym sym
String	String Str
Number	Number Num
Boolean	Boolean Bool
null	null
undefined	undefined
string	string str
number	number num
integer	integer int
float	float flt
boolean	boolean bool
NaN	NaN Nan naN nan

How Bundled Types are Determined

Thing a is said to be of type A if it passed the following checks:

1. It must pass built-in vanilla checks (if there's any).

   e.g.

   • Array.isArray() is a vanilla check for type Array.
   • typeof {} === "object" is a vanilla check for type Object.

2. a must be an instance of A if it's a complex type or the opposite if it's a primitive

   A.prototype must be somewhere in a's prototype chain.

   i.e.

   a instanceof A

   e.g.

   • new String is of type String because new String instanceof String yield true
   • "" is of type string because "" instanceof String yeilds false

   As a general rule, bundled types that have a primitive and complex pair are lower-cased and capitalized on the first letter, respectively.

Exceptions and caveats to the rules are as follows:

• typeof null === "object" does node apply for null
• types integer, Number, number, and float do not include NaN, NaN has it's own type
• Infinity is of type number, float, but not integer or Number