Simply get rid of all nulls in your code.
This is a clone of Scala's Option class to be used with flow.js.
// @flow
let valueA = Option.of(null).map(x => x + 2).getOrElse(() => 0);
// valueA = 0
let valueB = Some('any object').flatMap(x => Some(`${x}!!!`)).getOrUndefined();
// valueB = 'any object!!!'
let valueC = Some(null).flatMap(() => Option.of(2)).map(x => x * 3).getOrElse(() => 0);
// valueC = 6
let valueD = Some(1).mapNullable(() => null).getOrReturn(-1);
// valueD = -1
Some(1).equals(Some(1))
// true
None.equals(None)
// true
Some('abc').equals(None)
// false
None.isDefined; // false
Some(1).isDefined; // true
Some(1).isEmpty; // false
Some(null).isEmpty; // false! Option<null> is valid!
Some('foo').get(); // 'foo'
None.get(); // throws an error, use getOrElse or getOrUndefined instead
Some(3).filter(x => x % 2 === 0); // None
Some('bar').forEach(x => {
console.log(`my value: ${x}`);
});Represents optional values. Instances of Option are either an instance of Some or the object None.
$privateTokenany
Returns the option's value.
Type: function (): A
Returns true if the option is None, false otherwise.
Type: boolean
Returns true if the option is an instance of Some, false otherwise.
Type: boolean
Returns boolean
Returns a Some containing the result of applying f to this Option's value if this Option is nonempty.
ffunction (A): B
Returns Option<B>
Like map, but if resulting value is null, then returns None.
ffunction (A): B?
Returns Option<B>
Returns the result of applying f to this Option's value if this Option is nonempty. Returns None if this Option is empty. Slightly different from map in that f is expected to return an Option (which could be None).
ffunction (A): Option<B>
Returns Option<B>
Apply the given procedure f to the option's value, if it is nonempty.
ffunction (A): any
Returns void
Returns this Option if it is nonempty and applying the predicate to this Option's value returns true.
predicatefunction (A): boolean
Returns Option<A>
Returns the option's value if the option is nonempty, otherwise return the result of evaluating other.
otherfunction (): B
Returns (A | B)
Returns the option's value if the option is nonempty, otherwise return other.
otherB
Returns (A | B)
Returns the option's value if the option is nonempty, otherwise returns undefined.
Returns (A | void)
Compares the option's value with other option's value and returns true when they match. None always matches other None.
otherOption<B>
Returns boolean
Returns value if present, null otherwise. If value contains a method toJSON,
returns the result of method call.
Returns any
An Option factory which creates Some(x) if the argument is not null, and None if it is null.
valueV??
Returns Option<V>
The empty None object
Type: Option<any>
Creates Some(x). Note that Some(null) is valid.
Type: function (value: A): Option<A>
The empty None object.
Type: Option<any>
Creates Some(x). Note that Some(null) is valid.
valueA
Returns Option<A>