jorge a7910c81a8 | ||
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LICENSE | ||
README.md | ||
index.js | ||
package.json |
README.md
value-or-function
Normalize a value or function, applying extra args to the function
Example
var normalize = require('value-or-function');
// Values matching type are returned
var isEnabled = normalize('boolean', true);
// isEnabled === true
// Values not matching type return undefined
var isEnabled = normalize('boolean', 1);
// isEnabled === undefined
// 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
// Supply the function with context
var context = { c: 3 };
var count = normalize.call(context, 'number', function(a, b) {
return a + b + this.c;
}, 1, 2);
// count === 6
// Values one of multiple types are returned
var isEnabled = normalize(['string', 'boolean'], true);
// isEnabled === true
// Provide a function as first argument to do custom coercion
var now = new Date();
var enabledSince = normalize(function(value) {
if (value.constructor === Date) {
return value;
}
}, now);
// enabledSince === now
// Convenience methods are available for the built-in types
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.date(new Date());
API
normalize(coercer, value[, ...appliedArguments])
Takes a coercer function coercer
to transform value
to the desired type.
Also optionally takes any extra arguments to apply to value
if value
is a function.
If the return value of coercer(value)
is not null
or undefined
, that value is returned.
Otherwise, if value
is a function, that function is called with any extra arguments
supplied to normalize
, and its return value is passed through the coercer.
If coercer
is a string, it must be one of the built-in types (see below)
and the appropriate default coercer is invoked, optionally first reducing value
to a primitive type with .valueOf()
if it is an Object.
If coercer
is an array, each element is tried until one returns something other
than null
or undefined
, or it results in undefined
if all of the elements yield null
or undefined
.
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.date(value[, ...appliedArguments])
Convenience method for normalize('date', ...)
.
License
MIT