value-or-function

Normalize a value or function, applying extra args to the function

Example

var normalize = require('value-of-function');

// Values matching type are returned
var isEnabled = normalize('boolean', true);
// isEnabled === true

// Values not matching type return null
var isEnabled = normalize('boolean', 1);
// isEnabled === null

// Functions are called
var isEnabled = normalize('boolean', function() {
  return false;
});
// isEnabled === false

// Extra arguments are applied to function
var count = normalize('number', function(a, b) {
  return a + b;
}, 1, 2);
// count === 3

// Values one of multiple types are returned
var isEnabled = normalize(['string', 'boolean'], true);
// isEnabled === true

// Values matching predicate are returned
var now = new Date();
var enabledSince = normalize(function(value) {
  return value.constructor === Date;
}, now);
// enabledSince === now

// Convenience methods are available
var result = normalize.object({});
var result = normalize.number(1);
var result = normalize.string('');
var result = normalize.symbol(Symbol());
var result = normalize.boolean(true);
var result = normalize.function(function() {});
var result = normalize.undefined(undefined);
var result = normalize.date(new Date());
var result = normalize.date(1);

API

normalize(predicate, value[, ...appliedArguments])

Takes a predicate function predicate to test against value. Also optionally takes any extra arguments to apply to value if value is a function.

If the result of predicate(value) is true, the value is returned. If false and value is a function, the function is called with any extra arguments supplied to normalize.

If value is neither match for the predicate or a function, null is returned.

If value is a function and the result of calling the function does not match the predicate, null is returned.

If predicate is a string, the applied predicate is typeof value === predicate.

If predicate is an array, normalized is called with each element in turn until one matches or none matches.

normalize.object(value[, ...appliedArguments])

Convenience method for normalize('object', ...).

normalize.number(value[, ...appliedArguments])

Convenience method for normalize('number', ...).

normalize.string(value[, ...appliedArguments])

Convenience method for normalize('string', ...).

normalize.symbol(value[, ...appliedArguments])

Convenience method for normalize('symbol', ...).

normalize.boolean(value[, ...appliedArguments])

Convenience method for normalize('boolean', ...).

normalize.function(value[, ...appliedArguments])

Convenience method for normalize('function', ...).

normalize.undefined(value[, ...appliedArguments])

Convenience method for normalize('undefined', ...).

normalize.date(value[, ...appliedArguments])

Convenience method for normalize(dateOrTimestamp, ...) where dateOrTimestamp accepts both numbers and instances of Date.

License

MIT