conformant

Conformant

Conformant exports three functions:

• conform
• check
• instrument

Each of those functions takes three values:

• specs: a map of spec ids to specs
• spec: either an id from the map, or a spec
• value: some value which is checked against the spec

specs

a spec can be one of three things:

• a string, which is a reference to another spec
• a function, which is passed a value and returns true or false
• a formal spec using a command

commands

All specs can be resolved to a command, and all other specs can be resolved to the 'predicate' command.

A spec that uses a command is called a 'formal spec'. It is an array containing the command followed by its arguments.

Here are some examples of formal specs:

['predicate', value => value === 'Bob Zucchini'] ['keys', 'staleness', 'crustiness', 'yeast']

commands are passed an object with:

args

check

specs

predicate

Predicate takes one argument: a function.

Here's an example predicate: ['predicate', v => v === true]

function

A function spec takes one argument, a config object with up to three keys:

• args: a spec describing the arguments to the function
• ret: a spec describing the return value of the function
• fn: a predicate function passed ([...args], returnValue) describing the relationship between them

None of those keys are checkable until apply-time, so function specs are mostly useful with the provided instrument function, rather than check and conform.

or

and

keys

tuple

every

conformant.check

conformant.check takes three arguments, which may be passed separately:

• specs
• spec
• value

it returns true or false

conformant.conform

takes three arguments:

• specs
• spec
• value and returns either the value, if it satisfies the spec, or the string "conform/invalid"

conformant.instrument

instrument takes three arguments:

• specs
• spec -- must be a 'function' command spec
• function

it returns a modified function that checks its arguments, return value, and their relationshp against the config provided in the spec, and throws if they aren't satisfied.