133 lines
4.3 KiB
Markdown
133 lines
4.3 KiB
Markdown
|
<p align="center">
|
||
|
|
<a href="http://gulpjs.com">
|
||
|
|
<img height="257" width="114" src="https://raw.githubusercontent.com/gulpjs/artwork/master/gulp-2x.png">
|
||
|
|
</a>
|
||
|
|
</p>
|
||
|
|
|
||
|
|
# value-or-function
|
||
|
|
|
||
|
|
[![NPM version][npm-image]][npm-url] [![Downloads][downloads-image]][npm-url] [![Build Status][travis-image]][travis-url] [![AppVeyor Build Status][appveyor-image]][appveyor-url] [![Coveralls Status][coveralls-image]][coveralls-url] [![Gitter chat][gitter-image]][gitter-url]
|
||
|
|
|
||
|
|
Normalize a value or function, applying extra args to the function
|
||
|
|
|
||
|
|
## Example
|
||
|
|
|
||
|
|
```js
|
||
|
|
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
|
||
|
|
|
||
|
|
[downloads-image]: http://img.shields.io/npm/dm/value-or-function.svg
|
||
|
|
[npm-url]: https://npmjs.org/package/value-or-function
|
||
|
|
[npm-image]: http://img.shields.io/npm/v/value-or-function.svg
|
||
|
|
|
||
|
|
[travis-url]: https://travis-ci.org/gulpjs/value-or-function
|
||
|
|
[travis-image]: http://img.shields.io/travis/gulpjs/value-or-function.svg?label=travis-ci
|
||
|
|
|
||
|
|
[appveyor-url]: https://ci.appveyor.com/project/gulpjs/value-or-function
|
||
|
|
[appveyor-image]: https://img.shields.io/appveyor/ci/gulpjs/value-or-function.svg?label=appveyor
|
||
|
|
|
||
|
|
[coveralls-url]: https://coveralls.io/r/gulpjs/value-or-function
|
||
|
|
[coveralls-image]: http://img.shields.io/coveralls/gulpjs/value-or-function/master.svg
|
||
|
|
|
||
|
|
[gitter-url]: https://gitter.im/gulpjs/gulp
|
||
|
|
[gitter-image]: https://badges.gitter.im/gulpjs/gulp.png
|