Asserts

Assert must start with is(x) followed by the sequence of checks. First failed assert in sequence will throw an exception.

is(x).check1.check2...

Checks

Check is a function taking the value and returning boolean. Checks can be created with the same sequence of checks starting with is.

const { check } = is.check1.check2...

Simple type checks

• is.undefined
• is.integer
• is.number
• is.string
• is.boolean
• is.symbol
• is.function
• is.object
• is.array
• is.plainObject
• is.instanceOf( T )

Simple comparisons

• is.empty - x is null or undefined.
• is.falsy - !x.
• is.truthy - !!x.
• is.eq( y )
• is.le( y )
• is.lt
• is.ge
• is.gt
• is.stringLike( /regexp/ )

Deep object checks

• is.arrayOf( check )
• is.objectOf( check )
• is.shape( { a : check, b : value, ... } )

Combinators

• is.either( is.string, is.number, ... )