match (chain variant)

When match is called with 0 or 1 argument it returns a chainable instance for defining patterns to match on.

The main two methods are .with to add a branch to the matching, and .exec to run the match operation (which can be called multiple times, if desired).

import match from 'pattahn';
const r1 = match()
  .with('foo', 'is foo')
  .with('bar', 'is bar')
  .exec('foo');
// The value can alternatively be provided to match() as a single argument,
// if preferred for style.
const r2 = match('foo')
  .with('foo', 'is foo')
  .with('bar', 'is bar')
  .exec();
expect(r1).toBe('is foo');
expect(r2).toBe('is foo');

The first argument to .with is a condition, or a value supported by intoCondition.

The second argument is either a literal value, or a function that takes the output of the condition and returns the value. If the resulting value will be a function, then you need a function that returns a function.

Other methods

The .any takes the second argument to .with and matches on any input (i.e. the default case for a match). The call .any(result) is identical to .with(Test(() => true), result).

Both .any and .with return the matcher object to allow chaining.

The .clone method takes no arguments and returns a shallow clone of the matcher (where .clone().with(...) won't add a condition to the original).