assert

that

Signature

assert.that (value, validator, errorMessage)

Description

Assert that a value passes a validator function. Throws a TypeError with the given message if the validator returns false.

Parameters

Name	Type	Required	Description
value	*	yes	The value to validate
validator	function	yes	A function that returns true if the value is valid
errorMessage	string	yes	The error message thrown if validation fails

Returns

Type	Description
void

Examples

assert.that(5, (v) => v > 0, 'Value must be positive')  // passes
assert.that(-1, (v) => v > 0, 'Value must be positive') // throws TypeError: 'Value must be positive'
assert.that('hello', is.string, 'Must be a string')     // passes

all

Signature

assert.all (validations)

Description

Assert multiple validations at once. Iterates through the array and throws a TypeError at the first failing validation.

Parameters

Name	Type	Required	Description
validations	Array	yes	Array of validation objects
validations[].value	*	yes	The value to validate
validations[].validator	function	yes	The validator function
validations[].message	string	yes	The error message if validation fails

Returns

Type	Description
void

Examples

// passes
assert.all([
  { value: 'Alice', validator: (v) => is.nonEmptyString(v), message: 'name must be a non-empty string' },
  { value: 25, validator: is.positive, message: 'age must be positive' }
])

// throws TypeError: 'age must be positive'
assert.all([
  { value: 'Alice', validator: (v) => is.nonEmptyString(v), message: 'name must be a non-empty string' },
  { value: -1, validator: is.positive, message: 'age must be positive' }
])

any

Signature

assert.any (validations)

Description

Assert that at least one validation passes. Iterates through the array and throws a TypeError if none of the validators return true. The error message is built by joining all validation messages with or.

Parameters

Name	Type	Required	Description
validations	Array	yes	Array of validation objects
validations[].value	*	yes	The value to validate
validations[].validator	function	yes	The validator function
validations[].message	string	yes	The error message if this validation fails

Returns

Type	Description
void

Examples

// passes — value is a string
assert.any([
  { value: 'hello', validator: is.string, message: 'must be a string' },
  { value: 'hello', validator: is.array, message: 'must be an array' }
])

// throws TypeError: 'must be a string or must be an array'
assert.any([
  { value: 42, validator: is.string, message: 'must be a string' },
  { value: 42, validator: is.array, message: 'must be an array' }
])