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.